Matrix Sum (Obsolete)

Sum matrix elements along rows, columns, or entire input

Library

Math Functions / Matrices and Linear Algebra / Matrix Operations

dspobslib

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Description

The Matrix Sum block sums the elements of an M-by-N input matrix u along its rows, its columns, or over all its elements.

When the Sum over parameter is set to Rows, the block sums across the elements of each row and outputs the resulting M-by-1 matrix. A length-N 1-D vector input is treated as a 1-by-N matrix.

$$\left[\begin{array}{ccc}{u}_{11}& u_{12}& u_{13}\\ u_{21}& u_{22}& u_{23}\\ u_{31}& u_{32}& u_{33}\end{array}\right]\Rightarrow \left[\begin{array}{c}{y}_1\\ y_2\\ y_3\end{array}\right]=\left[\begin{array}{c}\left({\displaystyle \sum _{j=1}^3{u}_{1j}}\right)\\ \left({\displaystyle \sum _{j=1}^3{u}_{2j}}\right)\\ \left({\displaystyle \sum _{j=1}^3{u}_{3j}}\right)\end{array}\right]$$

When the Sum over parameter is set to Columns, the block sums down the elements of each column and outputs the resulting 1-by-N matrix. A length-M 1-D vector input is treated as a M-by-1 matrix.

$$\begin{array}{ccc}\left[\begin{array}{ccc}{u}_{11}& u_{12}& u_{13}\\ u_{21}& u_{22}& u_{23}\\ u_{31}& u_{32}& u_{33}\end{array}\right]& & \\ \Downarrow & & \\ \left[\begin{array}{ccc}{y}_1& y_2& y_3\end{array}\right]& =& \left[\begin{array}{ccc}\left({\displaystyle \sum _{i=1}^3{u}_{i1}}\right)& \left({\displaystyle \sum _{i=1}^3{u}_{i2}}\right)& \left({\displaystyle \sum _{i=1}^3{u}_{i3}}\right)\end{array}\right]\end{array}$$

When the Sum over parameter is set to Entire input, the block sums all the elements of the input together and outputs the resulting scalar.

$$\left[\begin{array}{ccc}{u}_{11}& u_{12}& u_{13}\\ u_{21}& u_{22}& u_{23}\\ u_{31}& u_{32}& u_{33}\end{array}\right]\Rightarrow y=({\displaystyle \sum _{i=1}^3{\displaystyle \sum _{j=1}^3{u}_{ij}}})$$

The output of the Matrix Sum block has the same frame status as the input. This block accepts real and complex fixed-point and floating-point inputs except for complex unsigned fixed-point inputs.

Fixed-Point Data Types

The following diagram shows the data types used within the Matrix Sum block for fixed-point signals.

You can set the accumulator and output data types in the block dialog as discussed in Dialog Box below.

Dialog Box

The Main pane of the Matrix Sum block dialog appears as follows.

Sum over

Indicate whether to sum the elements of each row, each column, or of the entire input.

The Fixed-point pane of the Matrix Sum block dialog appears as follows.

Rounding mode

Select the rounding mode for fixed-point operations.

Overflow mode

Select the overflow mode for fixed-point operations.

Accumulator

As depicted above, the elements of the block input are cast to the accumulator data type before they are added together. The output of the adder remains in the accumulator data type as each element of the input is added to it. Use this parameter to specify how you would like to designate this accumulator word and fraction lengths:

• When you select Inherit via internal rule, the accumulator word length and fraction length are calculated automatically. For information about how the accumulator word and fraction lengths are calculated when an internal rule is used, see Inherit via Internal Rule.

• When you select Same as input, these characteristics match those of the input to the block.

• When you select Binary point scaling, you can enter the word length and the fraction length of the accumulator, in bits.

• When you select Slope and bias scaling, you can enter the word length, in bits, and the slope of the accumulator. This block requires power-of-two slope and a bias of zero.

Output

Choose how you specify the output word length and fraction length:

• When you select Same as accumulator, these characteristics match those of the accumulator.

• When you select Same as input, these characteristics match those of the input to the block.

• When you select Binary point scaling, you can enter the word length and the fraction length of the output, in bits.

• When you select Slope and bias scaling, you can enter the word length, in bits, and the slope of the output. This block requires power-of-two slope and a bias of zero.

Lock scaling against changes by the autoscaling tool

Select this parameter to prevent any fixed-point scaling you specify in this block mask from being overridden by the autoscaling feature of the Fixed-Point Tool. See the fxptdlg (Fixed-Point Designer) reference page for more information.

Supported Data Types

Port	Supported Data Types
Input	Double-precision floating point Single-precision floating point Fixed point 8-, 16-, and 32-bit signed integers 8-, 16-, and 32-bit unsigned integers
Output	Double-precision floating point Single-precision floating point Fixed point 8-, 16-, and 32-bit signed integers 8-, 16-, and 32-bit unsigned integers