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| R2012a Documentation → Fixed-Point Toolbox | |
Learn more about Fixed-Point Toolbox |
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How to Use assert with fiaccel Rules for Using assert Function Example: Specifying Properties of Primary Fixed-Point Inputs |
You can use the MATLAB assert function to define properties of primary function inputs directly in your MATLAB file.
Use the assert function to invoke standard MATLAB functions for specifying the class, size, and complexity of primary function inputs.
assert ( isa ( param, 'class_name') )
Sets the input parameter param to the MATLAB class class_name. For example, to set the class of input U to a 32-bit signed integer, call:
... assert(isa(U,'embedded.fi')); ...
Note If you set the class of an input parameter to fi, you must also set its numerictype, see Specify numerictype of Fixed-Point Input. You can also set its fimath properties, see Specify fimath of Fixed-Point Input. If you do not set the fimath properties, fiaccel uses the MATLAB default fimath value. If you set the class of an input parameter to struct, you must specify the properties of each field in the structure in the order in which you define the fields in the structure definition. |
assert ( isfi ( param ) ) assert ( isa ( param, 'embedded.fi' ) )
Sets the input parameter param to the MATLAB class fi (fixed-point numeric object). For example, to set the class of input U to fi, call:
... assert(isfi(U)); ...
or
... assert(isa(U,'embedded.fi')); ...
Note If you set the class of an input parameter to fi, you must also set its numerictype, see Specify numerictype of Fixed-Point Input. You can also set its fimath properties, see Specify fimath of Fixed-Point Input. If you do not set the fimath properties, fiaccel uses the MATLAB default fimath value. |
assert ( isstruct ( param ) )
Sets the input parameter param to the MATLAB class struct (structure). For example, to set the class of input U to a struct, call:
... assert(isstruct(U)); ...
or
... assert(isa(U,'struct')); ...
Note If you set the class of an input parameter to struct, you must specify the properties of each field in the structure in the order in which you define the fields in the structure definition. |
assert ( all ( size (param) == [dims ] ) )
Sets the input parameter param to the size specified by dimensions dims. For example, to set the size of input U to a 3-by-2 matrix, call:
... assert(all(size(U)== [3 2])); ...
assert ( isscalar (param ) ) assert ( all ( size (param) == [ 1 ] ) )
Sets the size of input parameter param to scalar. For example, to set the size of input U to scalar, call:
... assert(isscalar(U)); ...
or
... assert(all(size(U)== [1])); ...
assert ( isreal (param ) )
Specifies that the input parameter param is real. For example, to specify that input U is real, call:
... assert(isreal(U)); ...
assert ( ~isreal (param ) )
Specifies that the input parameter param is complex. For example, to specify that input U is complex, call:
... assert(~isreal(U)); ...
assert ( isequal ( numerictype ( fiparam ), T ) )
Sets the numerictype properties of fi input parameter fiparam to the numerictype object T. For example, to specify the numerictype property of fixed-point input U as a signed numerictype object T with 32-bit word length and 30-bit fraction length, use the following code:
... % Define the numerictype object. T = numerictype(1, 32, 30); % Set the numerictype property of input U to T. assert(isequal(numerictype(U),T)); ...
assert ( isequal ( fimath ( fiparam ), F ) )
Sets the fimath properties of fi input parameter fiparam to the fimath object F. For example, to specify the fimath property of fixed-point input U so that it saturates on integer overflow, use the following code:
...
% Define the fimath object.
F = fimath('OverflowMode','saturate');
% Set the fimath property of input U to F.
assert(isequal(fimath(U),F));
... Note If you do not specify the fimath properties using assert, fiaccel uses the MATLAB default fimath value. |
assert ( function1 ( params ) && function2 ( params ) && function3 ( params ) && ... )
Specifies the class, size, and complexity of one or more inputs using a single assert function call. For example, the following code specifies that input U is a double, complex, 3-by-3 matrix, and input V is a 16-bit unsigned integer:
... assert(isa(U,'double') && ~isreal(U) && all(size(U) == [3 3]) && isa(V,'uint16')); ...
Follow these rules when using the assert function to specify the properties of primary function inputs:
Call assert functions at the beginning of the primary function, before any flow-control operations such as if statements or subroutine calls.
Do not call assert functions inside conditional constructs, such as if, for, while, and switch statements.
Use the assert function with fiaccel only for specifying properties of primary function inputs before converting your MATLAB code to MEX code.
If you set the class of an input parameter to fi:
You must also set its numerictype, see Specify numerictype of Fixed-Point Input.
You can also set its fimath properties, see Specify fimath of Fixed-Point Input. If you do not set the fimath properties, fiaccel uses the MATLAB default fimath value.
If you set the class of an input parameter to struct, you must specify the class, size, and complexity of each field in the structure in the order in which you define the fields in the structure definition.
In the following example, the primary MATLAB function emcsqrtfi takes one fixed-point input: x. The code specifies the following properties for this input:
| Property | Value |
|---|---|
| class | fi |
| numerictype | numerictype object T, as specified in the primary function |
| fimath | fimath object F, as specified in the primary function |
| size | scalar (by default) |
| complexity | real (by default) |
function y = emcsqrtfi(x)
T = numerictype('WordLength',32,'FractionLength',23,...
'Signed',true);
F = fimath('SumMode','SpecifyPrecision',...
'SumWordLength',32,'SumFractionLength',23,...
'ProductMode','SpecifyPrecision',...
'ProductWordLength',32,'ProductFractionLength',23);
assert(isfi(x));
assert(isequal(numerictype(x),T));
assert(isequal(fimath(x),F));
y = sqrt(x);Assume you have defined S as the following scalar MATLAB structure:
S = struct('r',double(1),'i',fi(4,true,8,0));This code specifies the class and size of S and its fields when passed as an input to your MATLAB function:
function y = fcn(S)
% Specify the class of the input as struct.
assert(isstruct(S));
% Specify the size of the fields r and i
% in the order in which you defined them.
T = numerictype('Wordlength', 8,'FractionLength', ...
0,'signed',true);
assert(isa(S.r,'double'));
assert(isfi(S.i) && isequal(numerictype(S.i),T));
y = S;Note In most cases, fiaccel uses defaults when you do not explicitly specify values for properties—except for structure fields. The only way to name a field in a structure is to set at least one of its properties. Therefore in the preceding example, an assert function specifies that field S.r is of type double, even though double is the default. |
For structure arrays, you must choose a representative element of the array for specifying the properties of each field. For example, assume you have defined S as the following 1-by-2 array of MATLAB structures:
S = struct('r',{double(1), double(2)},'i',...
{fi(4,1,8,0), fi(5,1,8,0)});The following code specifies the class and size of each field of structure input S using the first element of the array:
function y = fcn(S)
% Specify the class of the input S as struct.
assert(isstruct(S));
T = numerictype('Wordlength', 8,'FractionLength', ...
0,'signed',true);
% Specify the size of the fields r and i
% based on the first element of the array.
assert(all(size(S) == [1 2]));
assert(isa(S(1).r,'double'));
assert(isfi(S(1).i) && isequal(numerictype(S(1).i),T));
y = S;Note In most cases, fiaccel uses defaults when you don't explicitly specify values for properties — except for structure fields. The only way to name a field in a structure is to set at least one of its properties. Therefore in the example above, an assert function specifies that field S(1).r is of type double, even though double is the default. |
 | Generating MEX Functions from MATLAB Code That Uses Global Data | Controlling Run-Time Checks |  |
Learn how to apply early verification to your development process through these technical resources.
How much time do you spend on testing to ensure implementation meets system-level requirements?
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