Generate Single-Precision MATLAB Code
This example shows how to generate single-precision MATLAB® code from double-precision MATLAB code. This example shows the single-precision conversion workflow that you use when you want to see single-precision MATLAB code or use verification options. Optionally, you can also generate single-precision C/C++ code.
Prerequisites
To complete this example, install the following products:
MATLAB
MATLAB Coder™
Fixed-Point Designer™
C compiler
See Supported Compilers.
You can use
mex -setup
to change the default compiler. See Change Default Compiler.
Create a Folder and Copy Relevant Files
Create a local working folder, for example,
c:\ex_2ndOrder_filter
.Change to the
docroot\toolbox\fixpoint\examples
folder. At the MATLAB command line, enter:cd(fullfile(docroot, 'toolbox', 'fixpoint', 'examples'))
Copy the
ex_2ndOrder_filter.m
andex_2ndOrder_filter_test.m
files to your local working folder.Type Name Description Function code ex_2ndOrder_filter.m
Entry-point MATLAB function Test file ex_2ndOrder_filter_test.m
MATLAB script that tests
ex_2ndOrder_filter.m
Set Up the Single-Precision Configuration Object
Create a single-precision configuration object. Specify the test file name. Verify the single-precision code using the test file. Plot the error between the double-precision code and single-precision code. Use the default values for the other properties.
scfg = coder.config('single'); scfg.TestBenchName = 'ex_2ndOrder_filter_test'; scfg.TestNumerics = true; scfg.LogIOForComparisonPlotting = true;
Generate Single-Precision MATLAB Code
To convert the double-precision MATLAB function, ex_2ndOrder_filter
,
to single-precision MATLAB code, use the codegen
function with the -double2single
option.
codegen -double2single scfg ex_2ndOrder_filter
codegen
analyzes the double-precision
code. The conversion process infers types by running the test file
because you did not specify the input types for the ex_2ndOrder_filter
function.
The conversion process selects single-precision types for the double-precision
variables. It selects int32
for index variables.
When the conversion is complete, codegen
generates a type
proposal report.
View the Type Proposal Report
To see the types that the conversion process selected for the
variables, open the type proposal report for the ex_2ndOrder_filter
function.
Click the link ex_2ndOrder_filter_report.html
.
The report opens in a web browser. The conversion process converted:
Double-precision variables to
single
.The index
i
toint32
. The conversion process casts index and dimension variables toint32
.
View Generated Single-Precision MATLAB Code
To view the report for the generation of the single-precision MATLAB code, in the Command Window:
Scroll to the
Generate Single-Precision Code
step. Click the View report link.In the MATLAB Source pane, click
ex_2ndOrder_filter_single
.
The code generation report displays the single-precision MATLAB code
for ex_2ndOrder_filter
.
View Potential Data Type Issues
When you generate single-precision code, codegen
enables highlighting of potential
data type issues in code generation reports. If codegen
cannot remove a double-precision
operation, the report highlights the MATLAB expression that results in the operation. Click the Code
Insights tab. The absence of potential data type issues indicates that
no double-precision operations remain.
Compare the Double-Precision and Single-Precision Variables
You can see the comparison plots for the input x
and
output y
because you selected to log inputs and
outputs for comparison plots .
Optionally Generate Single-Precision C Code
If you also want to generate single-precision C code, create
a code configuration object for C code generation. Use this configuration
object with the -config
option of the codegen
function.
For example:
Create a code configuration object for generation of a C static library.
cfg = coder.config('lib');
Generate the C code. Enable generation of the code generation report.
codegen -double2single scfg -config cfg ex_2ndOrder_filter -report
To view the code generation report for the C code generation, click the View Report link.
In the Generated Code pane, click
ex_2ndOrder_filter.c
.Double-precision variables have type
float
in the C code.The index
i
is an integer.
When you generate single-precision code,
codegen
enables highlighting of potential data type issues in the code generation report. Ifcodegen
cannot remove a double-precision operation, the report highlights the MATLAB expression that results in the operation.Click the Code Insights tab. Then, expand Potential data type issues. The absence of double-precision operations indicates that no double-precision operations remain.
See Also
coder.SingleConfig
| codegen
| coder.config
Related Examples
- Generate Single-Precision C Code Using the MATLAB Coder App
- Generate Single-Precision C Code at the Command Line