DSP Blockset

Constant Diagonal Matrix

Generate a square, diagonal matrix

Library

• DSP Sources
• Math Functions / Matrices and Linear Algebra / Matrix Operations

Description

The Constant Diagonal Matrix block outputs a square diagonal matrix constant. The Constant along diagonal parameter determines the values along the matrix diagonal. This parameter can be a scalar to be repeated for all elements along the diagonal, or a vector containing the values of the diagonal elements. To generate the identity matrix, set the Constant along diagonal to 1, or use the Identity Matrix block.

The output is frame based when the Frame-based output check box is selected; otherwise, the output is sample based.

Dialog Box

Opening this dialog box causes a running simulation to pause. See Changing Source Block Parameters in the online Simulink documentation for details.

Constant(s) along diagonal

Specify the values of the elements along the diagonal. You can input a scalar or a vector. Tunable.

If you specify any data type information in this field, it is overridden by the value of the Output data type parameter.

Frame-based output

Select to cause the output of the block to be frame based. Otherwise, the output is sample based.

Show additional parameters

If selected, additional parameters specific to implementation of the block become visible as shown.

Allow overrides from DSP Fixed-Point Attributes blocks

If you select this parameter, and if the Output data type parameter is set to Fixed-point, fixed-point data types for this block may be set by DSP Fixed-Point Attributes blocks in your model. If this parameter is unselected, the data types are always set by the parameters in the block mask.

Output data type

Specify the output data type in one of the following ways:

• Choose one of the built-in data types from the drop-down list.
• Choose Fixed-point to specify the output data type and scaling in the Word length, Set fraction length in output to, and Fraction length parameters.
• Choose User-defined to specify the output data type and scaling in the User-defined data type, Set fraction length in output to, and Fraction length parameters.
• Choose Inherit from `Constant(s) along diagonal' to set the output data type and scaling to match the values of the Constant(s) along diagonal parameter.
• Choose Inherit via back propagation to set the output data type and scaling to match the next block downstream.
  The value of this parameter overrides any data type information specified in the Constant(s) along diagonal parameter.

Word length

Specify the word length, in bits, of the fixed-point output data type. This parameter is only visible if Fixed-point is selected for the Output data type parameter.

User-defined data type

Specify any built-in or fixed-point data type. You can specify fixed-point data types using the sfix, ufix, sint, uint, sfrac, and ufrac functions from the Fixed-Point Blockset. This parameter is only visible if User-defined is selected for the Output data type parameter.

Set fraction length in output to

Specify the scaling of the fixed-point output by either of the following two methods:

• Choose Best precision to have the output scaling automatically set such that the output signal has the best possible precision.
• Choose User-defined to specify the output scaling in the Fraction length parameter.
  This parameter is only visible if Fixed-point or User-defined is selected for the Output data type parameter, and if the specified output data type is a fixed-point data type.

Fraction length

For fixed-point output data types, specify the number of fractional bits, or bits to the right of the binary point. This parameter is only visible if Fixed-point or User-defined is selected for the Output data type parameter, and if User-defined is selected for the Set fraction length in output to parameter.

Supported Data Types

• Double-precision floating point
• Single-precision floating point
• Fixed point
• 8-, 16-, and 32-bit signed integers
• 8-, 16-, and 32-bit unsigned integers

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

See Also

Create Diagonal Matrix	DSP Blockset
DSP Constant	DSP Blockset
Identity Matrix	DSP Blockset
diag	MATLAB

Also see Creating Signals Using Constant Blocks for how to use this and other blocks to generate constant signals.

Complex Exponential

Constant Ramp