Overwrite Values (DSP Blockset)

Overwrite a submatrix or subdiagonal of the input.

Library

Math Functions / Matrices and Linear Algebra / Matrix Operations
Signal Management / Indexing

Description

The Overwrite Values block overwrites a contiguous submatrix or subdiagonal of an input matrix. You can provide the overwriting values by typing them in a block parameter, or through an additional input port (useful for providing overwriting values that change at each time step).

The block accepts both sample- and frame-based vectors and matrices. The output has the same size and frame status as the original input signal (not necessarily the same size and frame status as the signal containing the overwriting values).

Sections of This Reference Page

Specifying the Overwriting Values

The Source of overwriting value(s) parameter determines how you must provide the overwriting values, and has the following settings.

Specify via dialog -- You must provide the overwriting value(s) in the Overwrite with parameter. The block uses the same overwriting values to overwrite the specified portion of the input at each time step. To learn how to specify valid overwriting values, see Valid Overwriting Values.
Second input port -- You must provide overwriting values through a second block input port, V. Use this setting to provide different overwriting values at each time step. (The output inherits its size, rate, and frame status from the input signal, not the overwriting values.)

The rate at which you provide the overwriting values through input port V must match the rate at which the block receives each input matrix at input port A. The rate requirements depend on whether the input signal and overwriting values signal have the same frame status:
- If both signals are sample based, their sample rates must be the same.
- If both signals are frame based, their frame rates must be the same.
- If one signal is sample-based and one signal is frame based, the sample rate of the sample-based signal must be the same as the frame rate of the frame-based signal.

Valid Overwriting Values. The overwriting values can be a single constant, vector, or matrix, depending on the portion of the input you are overwriting, regardless of whether you provide the overwriting values through an input port or by providing them in the Overwrite with parameter.

Table 7-15: Valid Overwriting Values
Portion of Input to Overwrite
Valid Overwriting Values
Example

A single element in the input

Any constant value, v

v = 9

A length-k portion of the diagonal

Any length-k column or row vector, v

A length-k portion of a row

Any length-k row vector, v

A length-k portion of a column

Any length-k column vector, v

An m-by-n submatrix

Any m-by-n matrix, v

**Table 7-15: Valid Overwriting Values**
Portion of Input to Overwrite	Valid Overwriting Values	Example
A single element in the input	Any constant value, v	v `= 9`
A length-k portion of the diagonal	Any length-k column or row vector, v
A length-k portion of a row	Any length-k row vector, v
A length-k portion of a column	Any length-k column vector, v
An m-by-n submatrix	Any m-by-n matrix, v

Overwriting a Submatrix

To overwrite a submatrix, do the following:

Set the Overwrite parameter to Submatrix.
Specify the overwriting values as described in Specifying the Overwriting Values.
Specify which rows and columns of the input matrix are contained in the submatrix that you want to overwrite by setting the Row span parameter to one of the following options (and the Column span to the analogous column-related options):

All rows -- The submatrix contains all rows of the input matrix.
One row -- The submatrix contains only one row of the input matrix, which you must specify in the Row parameter, as described in the following table.
Range of rows -- The submatrix contains one or more rows of the input, which you must specify in the Starting Row and Ending row parameters, as described in the following tables.

If you set Row span to One row or Range of rows, you need to further specify the row(s) contained in the submatrix by setting the Row or Starting row and Ending row parameters. Likewise, if you set Column span to One column or Range of columns, you must further specify the column(s) contained in the submatrix by setting the Column or Starting column and Ending column parameters. For descriptions of the settings for these parameters, see Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters, and Table 7-17, Settings for Ending Row and Ending Column Parameters,.

Table 7-16: Settings for Row, Column, Starting Row, and Starting Column Parameters
Settings for Specifying the Submatrix's First Row or Column
First Row of Submatrix
(Only row for Row span = One row)
First Column of Submatrix
(Only row for Row span = One row)

First
First row of the input
First column of the input

Index
Input row specified in the Row index parameter
Input column specified in the Column index parameter

Offset from last
Input row with the index
M - rowOffsetwhere M is the number of input rows, and rowOffset is the value of the Row offset or Starting row offset parameter
Input column with the index
N - colOffsetwhere N is the number of input columns, and colOffset is the value of the Column offset or Starting column offset parameter

Last
Last row of the input
Last column of the input

Offset from middle
Input row with the index
floor(M/2 + 1 - rowOffset)where M is the number of input rows, and rowOffset is the value of the Row offset or Starting row offset parameter
Input column with the index
floor(N/2 + 1 - rowOffset)where N is the number of input columns, and colOffset is the value of the or Column offset or Starting column offset parameter

Middle
Input row with the index
floor(M/2 + 1)where M is the number of input rows
Input columns with the index
floor(N/2 + 1)where N is the number of input columns

**Table 7-16: Settings for Row, Column, Starting Row, and Starting Column Parameters**
Settings for Specifying the Submatrix's First Row or Column	First Row of Submatrix (Only row for Row span = One row)	First Column of Submatrix (Only row for Row span = One row)
First	First row of the input	First column of the input
Index	Input row specified in the Row index parameter	Input column specified in the Column index parameter
Offset from last	Input row with the index `M` - `rowOffset`where `M` is the number of input rows, and `rowOffset` is the value of the Row offset or Starting row offset parameter	Input column with the index `N` - `colOffset`where `N` is the number of input columns, and `colOffset` is the value of the Column offset or Starting column offset parameter
Last	Last row of the input	Last column of the input
Offset from middle	Input row with the index `floor(M/2 + 1 - rowOffset)`where `M` is the number of input rows, and `rowOffset` is the value of the Row offset or Starting row offset parameter	Input column with the index `floor(N/2 + 1 - rowOffset)`where `N` is the number of input columns, and `colOffset` is the value of the or Column offset or Starting column offset parameter
Middle	Input row with the index `floor(M/2 + 1)`where `M` is the number of input rows	Input columns with the index `floor(N/2 + 1)`where `N` is the number of input columns

Table 7-17: Settings for Ending Row and Ending Column Parameters
Settings for Specifying the Submatrix's Last Row or Column
Last Row of Submatrix
Last Column of Submatrix

Index
Input row specified in the Ending row index parameter
Input column specified in the Ending column index parameter

Offset from last
Input row with the index
M - rowOffsetwhere M is the number of input rows, and rowOffset is the value of the Ending row offset parameter
Input column with the index
N - colOffsetwhere N is the number of input columns, and colOffset is the value of the Ending column offset parameter

Last
Last row of the input
Last column of the input

Offset from middle
Input row with the index
floor(M/2 + 1 - rowOffset)where M is the number of input rows, and rowOffset is the value of the Ending row offset parameter
Input column with the index
floor(N/2 + 1 - rowOffset)where N is the number of input columns, and colOffset is the value of the Ending column offset parameter

Middle
Input row with the index
floor(M/2 + 1)where M is the number of input rows
Input columns with the index
floor(N/2 + 1)where N is the number of input columns

**Table 7-17: Settings for Ending Row and Ending Column Parameters**
Settings for Specifying the Submatrix's Last Row or Column	Last Row of Submatrix	Last Column of Submatrix
Index	Input row specified in the Ending row index parameter	Input column specified in the Ending column index parameter
Offset from last	Input row with the index `M` - `rowOffset`where `M` is the number of input rows, and `rowOffset` is the value of the Ending row offset parameter	Input column with the index `N` - `colOffset`where `N` is the number of input columns, and `colOffset` is the value of the Ending column offset parameter
Last	Last row of the input	Last column of the input
Offset from middle	Input row with the index `floor(M/2 + 1 - rowOffset)`where `M` is the number of input rows, and `rowOffset` is the value of the Ending row offset parameter	Input column with the index `floor(N/2 + 1 - rowOffset)`where `N` is the number of input columns, and `colOffset` is the value of the Ending column offset parameter
Middle	Input row with the index `floor(M/2 + 1)`where `M` is the number of input rows	Input columns with the index `floor(N/2 + 1)`where `N` is the number of input columns

Overwriting a Subdiagonal

To overwrite a subdiagonal, do the following:

Set the Overwrite parameter to Diagonal.
Specify the overwriting values as described in Specifying the Overwriting Values.
Specify the subdiagonal that you want to overwrite by setting the Diagonal span parameter to one of the following options:

All elements -- Overwrite the entire input diagonal.
One element -- Overwrite one element in the diagonal, which you must specify in the Element parameter (described below).
Range of elements -- Overwrite a portion of the input diagonal, which you must specify in the Starting element and Ending element parameters, as described in the following table.

If you set Diagonal span to One element or Range of elements, you need to further specify which diagonal element(s) to overwrite by setting the Element or Starting element and Ending element parameters. See Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters, and Table 7-17, Settings for Ending Row and Ending Column Parameters,.

Table 7-18: Element and Starting Element Parameters
Settings for Element and Starting Element Parameters
First Element in Subdiagonal
(Only element if Diagonal span = One element)

First
Diagonal element in first row of the input

Index
kth diagonal element, where k is the value of the Element index or Starting element index parameter

Offset from last
Diagonal element in the row with the index
M - offsetwhere M is the number of input rows, and offset is the value of the Element offset or Starting element offset parameter

Last
Diagonal element in the last row of the input

Offset from middle
Diagonal element in the input row with the index
floor(M/2 + 1 - offset)where M is the number of input rows, and offset is the value of the Element offset or Starting element offset parameter

Middle
Diagonal element in the input row with the index
floor(M/2 + 1)where M is the number of input rows

**Table 7-18: Element and Starting Element Parameters**
Settings for Element and Starting Element Parameters	First Element in Subdiagonal (Only element if Diagonal span = One element)
First	Diagonal element in first row of the input
Index	kth diagonal element, where k is the value of the Element index or Starting element index parameter
Offset from last	Diagonal element in the row with the index `M` - `offset`where `M` is the number of input rows, and `offset` is the value of the Element offset or Starting element offset parameter
Last	Diagonal element in the last row of the input
Offset from middle	Diagonal element in the input row with the index `floor(M/2 + 1 - offset)`where `M` is the number of input rows, and `offset` is the value of the Element offset or Starting element offset parameter
Middle	Diagonal element in the input row with the index `floor(M/2 + 1)`where `M` is the number of input rows

Table 7-19: Ending Element Parameter
Settings for Ending Element Parameter
Last Element in Subdiagonal

Index
kth diagonal element, where k is the value of the Ending element index parameter

Offset from last
Diagonal element in the row with the index
M - offsetwhere M is the number of input rows, and offset is the value of the Ending element offset parameter

Last
Diagonal element in the last row of the input

Offset from middle
Diagonal element in the input row with the index
floor(M/2 + 1 - offset)where M is the number of input rows, and offset is the value of the Ending element offset parameter

Middle
Diagonal element in the input row with the index
floor(M/2 + 1)where M is the number of input rows

**Table 7-19: Ending Element Parameter**
Settings for Ending Element Parameter	Last Element in Subdiagonal
Index	kth diagonal element, where k is the value of the Ending element index parameter
Offset from last	Diagonal element in the row with the index `M` - `offset`where `M` is the number of input rows, and `offset` is the value of the Ending element offset parameter
Last	Diagonal element in the last row of the input
Offset from middle	Diagonal element in the input row with the index `floor(M/2 + 1 - offset)`where `M` is the number of input rows, and `offset` is the value of the Ending element offset parameter
Middle	Diagonal element in the input row with the index `floor(M/2 + 1)`where `M` is the number of input rows

Example

To overwrite the lower-right 2-by-3 submatrix of a 3-by-5 input matrix with all zeros, enter the following set of parameters:

Overwrite = Submatrix
Source of overwriting value(s) = Specify via dialog
Overwrite with = 0
Row span = Range of rows
Starting row = Index
Starting row index = 2
Ending row = Last
Column span = Range of columns
Starting column = Offset from last
Starting column offset = 2
Ending column = Last

The figure below shows the block with the above settings overwriting a portion of a 3-by-5 input matrix.

There are often several possible parameter combinations that select the same submatrix from the input. For example, instead of specifying Last for Ending column, you could select the same submatrix by specifying

Ending column = Index
Ending column index = 5

Dialog Box

Note Only some of the following parameters are visible in the dialog box at any one time.

Overwrite: Determines whether to overwrite a specified submatrix or a specified portion of the diagonal.
Source of overwriting value(s): Determines where you must provide the overwriting values: either through an input port, or by providing them in the Overwrite with parameter. For more information, see Specifying the Overwriting Values.
Overwrite with: The value(s) with which to overwrite the specified portion of the input matrix. Enabled only when Source of overwriting value(s) is set to Specify via dialog. To learn how to specify valid overwriting values, see Valid Overwriting Values.
Row span: The range of input rows to be overwritten. Options are All rows, One row, or Range of rows. For descriptions of these options, see Overwriting a Submatrix.
Row/Starting row: The input row that is the first row of the submatrix that the block overwrites. For a description of the options for the Row and Starting row parameters, see Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters,. (Row is enabled when Row span is set to One row, and Starting row when Row span is set to Range of rows.)
Row index/Starting row index: Index of the input row that is the first row of the submatrix that the block overwrites. See how to use these parameters in Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters,. (Row index is enabled when Row is set to Index, and Starting row index when Starting row is set to Index.)
Row offset/Starting row offset: The offset of the input row that is the first row of the submatrix that the block overwrites. See how to use these parameters in Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters,. (Row offset is enabled when Row is set to Offset from middle or Offset from last, and Starting row offset is enabled when Starting row is set to Offset from middle or Offset from last.)
Ending row: The input row that is the last row of the submatrix that the block overwrites. For a description of this parameter's options, see Table 7-17, Settings for Ending Row and Ending Column Parameters,. (Enabled when Row span is set to Range of rows, and Starting row is set to any option but Last.)
Ending row index: Index of the input row that is the last row of the submatrix that the block overwrites. See how to use this parameter in Table 7-17, Settings for Ending Row and Ending Column Parameters,. (Enabled when Ending row is set to Index.)
Ending row offset: The offset of the input row that is the last row of the submatrix that the block overwrites. See how to use this parameter in Table 7-17, Settings for Ending Row and Ending Column Parameters,. (Enabled when Ending row is set to Offset from middle or Offset from last.)
Column span: The range of input columns to be overwritten. Options are All columns, One column, or Range of columns. For descriptions of the analogous row options, see Overwriting a Submatrix.
Column/Starting column: The input column that is the first column of the submatrix that the block overwrites. For a description of the options for the Column and Starting column parameters, see Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters,. (Column is enabled when Column span is set to One column, and Starting column when Column span is set to Range of columns.)
Column index/Starting column index: Index of the input column that is the first column of the submatrix that the block overwrites. See how to use these parameters in Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters,. (Column index is enabled when Column is set to Index, and Starting column index when Starting column is set to Index.)
Column offset/Starting column offset: The offset of the input column that is the first column of the submatrix that the block overwrites. See how to use these parameters in Table 7-16, Settings for Row, Column, Starting Row, and Starting Column Parameters,. (Column offset is enabled when Column is set to Offset from middle or Offset from last, and Starting column offset is enabled when Starting column is set to Offset from middle or Offset from last.)
Ending column: The input column that is the last column of the submatrix that the block overwrites. For a description of this parameter's options, see Table 7-17, Settings for Ending Row and Ending Column Parameters,. (Enabled when Column span is set to Range of columns, and Starting column is set to any option but Last.)
Ending column index: Index of the input column that is the last column of the submatrix that the block overwrites. See how to use this parameter in Table 7-17, Settings for Ending Row and Ending Column Parameters,. (Enabled when Ending column is set to Index.)
Ending column offset: The offset of the input column that is the last column of the submatrix that the block overwrites. See how to use this parameter in Table 7-17, Settings for Ending Row and Ending Column Parameters,. (Enabled when Ending column is set to Offset from middle or Offset from last.)
Diagonal span: The range of diagonal elements to be overwritten. Options are All elements, One element, or Range of elements. For descriptions of these options, see Overwriting a Subdiagonal.
Element/Starting element: The input diagonal element that is the first element in the subdiagonal that the block overwrites. For a description of the options for the Element and Starting element parameters, see Table 7-18, Element and Starting Element Parameters,. (Element is enabled when Element span is set to One element, and Starting element when Element span is set to Range of elements.)
Element index/Starting element index: Index of the input diagonal element that is the first element of the subdiagonal that the block overwrites. See how to use these parameters in Table 7-18, Element and Starting Element Parameters,. (Element index is enabled when Element is set to Index, and Starting element index when Starting element is set to Index.)
Element offset/Starting element offset: The offset of the input diagonal element that is the first element of the subdiagonal that the block overwrites. See how to use these parameters in Table 7-18, Element and Starting Element Parameters,. (Element offset is enabled when Element is set to Offset from middle or Offset from last, and Starting element offset is enabled when Starting element is set to Offset from middle or Offset from last.)
Ending element: The input diagonal element that is the last element of the subdiagonal that the block overwrites. For a description of this parameter's options, see Table 7-19, Ending Element Parameter,. (Enabled when Element span is set to Range of elements, and Starting element is set to any option but Last.)
Ending element index: Index of the input diagonal element that is the last element of the subdiagonal that the block overwrites. See how to use this parameter in Table 7-19, Ending Element Parameter,. (Enabled when Ending element is set to Index.)
Ending element offset: The offset of the input diagonal element that is the last element of the subdiagonal that the block overwrites. See how to use this parameter in Table 7-19, Ending Element Parameter,. (Enabled when Ending element is set to Offset from middle or Offset from last.)

Supported Data Types

Double-precision floating point
Single-precision floating point
Fixed-point
Custom data types
Boolean
8-, 16-, and 32-bit signed integers
8-, 16-, and 32-bit unsigned integers

To learn how to convert to the above data types in MATLAB and Simulink, see Supported Data Types and How to Convert to Them.

See Also

Reshape
Simulink

Selector
Simulink

Submatrix
DSP Blockset

Variable Selector
DSP Blockset

reshape
MATLAB

Reshape	Simulink
Selector	Simulink
Submatrix	DSP Blockset
Variable Selector	DSP Blockset
`reshape`	MATLAB

Also see Matrix Operations and Indexing for lists of all the blocks in these libraries.

Overlap-Save FFT Filter Pad