在Matlab中使用mex函数进行C/C++混合编程
最近写了个Matlab程序，好慢呐……所以开始学习Matlab与C/C++混合编程。下面写了个测试代码，显示一个Double类型矩阵中的元素。
源代码
- #include "mex.h"
- void displaySubscript( const mxArray *pArray, mwSize index );
- // 入口函数
- void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[] ) {
- // 源文件名后缀为.c时，所有变量声明必须一次性完成，且放在最前面, 否则mex编译错误
- // 源文件名后缀为.cpp时，没有上面的问题，...- -||
- double *pData;
- mwSize i;
- // 输入参数必须为一个，且为double类型
- if ( nrhs != 1 || mxDOUBLE_CLASS != mxGetClassID(prhs[0]) ) {
- mexErrMsgTxt( "输入参数不合法……" );
- }
- // 获取数据指针
- pData = mxGetPr(prhs[0]);
- // 遍历所有元素并打印到屏幕
- for ( i = 0; i != mxGetNumberOfElements(prhs[0]); i++ ) {
- displaySubscript( prhs[0], i );
- mexPrintf( " = %g/n", pData[i] );
- }
- }
- void displaySubscript( const mxArray *pArray, mwSize index ) {
- // 源文件名后缀为.c时，所有变量声明必须一次性完成，且放在最前面, 否则mex编译错误
- // 源文件名后缀为.cpp时，没有上面的问题，...- -||，代码好龊...
- mwSize i, j;
- mwSize numOfDim;
- mwSize *subScript;
- mwSize subIndex;
- mwSize total;
- const mwSize *Dims;
- const char *className;
- // 获取维度个数
- numOfDim = mxGetNumberOfDimensions(pArray);
- // 获取维度数组
- Dims = mxGetDimensions(pArray);
- // 获取类型名称
- className = mxGetClassName(pArray);
- // 分配下标数组内存
- subScript = (mwSize *)mxCalloc( numOfDim, sizeof( mwSize ) );
- // 根据当前的索引号生成下标
- subIndex = index;
- for ( i = numOfDim - 1; ; i-- ) {
- total = 1;
- for ( j = 0; j < i; j++ ) {
- total *= Dims[j];
- }
- subScript[i] = subIndex / total;
- subIndex = subIndex % total;
- if ( 0 == i ) {
- break;
- }
- }
- // 打印出所有下标
- mexPrintf( "(" );
- for ( i = 0; i < numOfDim - 1; i++ ) {
- mexPrintf( "%d,", subScript[i] + 1 );
- }
- mexPrintf( "%d)", subScript[numOfDim-1] + 1 );
- // 释放下标数组内存
- mxFree( subScript );
- }
在Matlab使用mex命令编译源文件时，要注意这样一个现象：源文件名后缀为.c时，所有变量声明必须一次性完成，且放在最前面, 否则mex编译错误；而源文件名后缀为.cpp时，就没有上面的问题，...- -||。
实验结果
混合编程API一览
MX Matrix Library
| mwIndex (C and Fortran) |
Type for index values |
| mwPointer (Fortran) |
Pointer type for platform |
| mwSignedIndex (C and Fortran) |
Signed integer type for size values |
| mwSize (C and Fortran) |
Type for size values |
| mxAddField (C and Fortran) |
Field to structure array |
| mxArray (C and Fortran) |
Type for MATLAB array |
| mxArrayToString (C) |
Convert array to string |
| mxAssert (C) |
Check assertion value for debugging purposes |
| mxAssertS (C) |
Check assertion value without printing assertion text |
| mxCalcSingleSubscript (C and Fortran) |
Offset from first element to desired element |
| mxCalloc (C and Fortran) |
Allocate dynamic memory for array using MATLAB memory manager |
| mxChar (C) |
Type for string array |
| mxClassID (C) |
Enumerated value identifying class of array |
| mxClassIDFromClassName (Fortran) |
Identifier corresponding to class |
| mxComplexity (C) |
Flag specifying whether array has imaginary components |
| mxCopyCharacterToPtr (Fortran) |
CHARACTER values from Fortran array to pointer array |
| mxCopyComplex16ToPtr (Fortran) |
COMPLEX*16 values from Fortran array to pointer array |
| mxCopyComplex8ToPtr (Fortran) |
COMPLEX*8 values from Fortran array to pointer array |
| mxCopyInteger1ToPtr (Fortran) |
INTEGER*1 values from Fortran array to pointer array |
| mxCopyInteger2ToPtr (Fortran) |
INTEGER*2 values from Fortran array to pointer array |
| mxCopyInteger4ToPtr (Fortran) |
INTEGER*4 values from Fortran array to pointer array |
| mxCopyPtrToCharacter (Fortran) |
CHARACTER values from pointer array to Fortran array |
| mxCopyPtrToComplex16 (Fortran) |
COMPLEX*16 values from pointer array to Fortran array |
| mxCopyPtrToComplex8 (Fortran) |
COMPLEX*8 values from pointer array to Fortran array |
| mxCopyPtrToInteger1 (Fortran) |
INTEGER*1 values from pointer array to Fortran array |
| mxCopyPtrToInteger2 (Fortran) |
INTEGER*2 values from pointer array to Fortran array |
| mxCopyPtrToInteger4 (Fortran) |
INTEGER*4 values from pointer array to Fortran array |
| mxCopyPtrToPtrArray (Fortran) |
Pointer values from pointer array to Fortran array |
| mxCopyPtrToReal4 (Fortran) |
REAL*4 values from pointer array to Fortran array |
| mxCopyPtrToReal8 (Fortran) |
REAL*8 values from pointer array to Fortran array |
| mxCopyReal4ToPtr (Fortran) |
REAL*4 values from Fortran array to pointer array |
| mxCopyReal8ToPtr (Fortran) |
REAL*8 values from Fortran array to pointer array |
| mxCreateCellArray (C and Fortran) |
Unpopulated N-D cell array |
| mxCreateCellMatrix (C and Fortran) |
Unpopulated 2-D cell array |
| mxCreateCharArray (C and Fortran) |
Unpopulated N-D string array |
| mxCreateCharMatrixFromStrings (C and Fortran) |
Create populated 2-D string array |
| mxCreateDoubleMatrix (C and Fortran) |
2-D, double-precision, floating-point array initialized to 0 |
| mxCreateDoubleScalar (C and Fortran) |
Scalar, double-precision array initialized to specified value |
| mxCreateLogicalArray (C) |
N-D logical array initialized to false |
| mxCreateLogicalMatrix (C) |
2-D, logical array initialized to false |
| mxCreateLogicalScalar (C) |
Scalar, logical array |
| mxCreateNumericArray (C and Fortran) |
Unpopulated N-D numeric array |
| mxCreateNumericMatrix (C and Fortran) |
Numeric matrix initialized to 0 |
| mxCreateSparse (C and Fortran) |
2-D unpopulated sparse array |
| mxCreateSparseLogicalMatrix (C) |
Unpopulated 2-D, sparse, logical array |
| mxCreateString (C and Fortran) |
Create 1-by-N array initialized to specified string |
| mxCreateStructArray (C and Fortran) |
Unpopulated N-D structure array |
| mxCreateStructMatrix (C and Fortran) |
Unpopulated 2-D structure array |
| mxDestroyArray (C and Fortran) |
Free dynamic memory allocated by MXCREATE* functions |
| mxDuplicateArray (C and Fortran) |
Make deep copy of array |
| mxFree (C and Fortran) |
Free dynamic memory allocated by MXCALLOC, MXMALLOC, or MXREALLOC functions |
| mxGetCell (C and Fortran) |
Contents of array cell |
| mxGetChars (C) |
Pointer to character array data |
| mxGetClassID (C and Fortran) |
Class of array |
| mxGetClassName (C and Fortran) |
Class of array as string |
| mxGetData (C and Fortran) |
Pointer to real data |
| mxGetDimensions (C and Fortran) |
Pointer to dimensions array |
| mxGetElementSize (C and Fortran) |
Number of bytes required to store each data element |
| mxGetEps (C and Fortran) |
Value of EPS |
| mxGetField (C and Fortran) |
Field value, given field name and index, into structure array |
| mxGetFieldByNumber (C and Fortran) |
Field value, given field number and index, into structure array |
| mxGetFieldNameByNumber (C and Fortran) |
Field name, given field number, in structure array |
| mxGetFieldNumber (C and Fortran) |
Field number, given field name, in structure array |
| mxGetImagData (C and Fortran) |
Pointer to imaginary data of array |
| mxGetInf (C and Fortran) |
Value of infinity |
| mxGetIr (C and Fortran) |
Sparse matrix IR array |
| mxGetJc (C and Fortran) |
Sparse matrix JC array |
| mxGetLogicals (C) |
Pointer to logical array data |
| mxGetM (C and Fortran) |
Number of rows in array |
| mxGetN (C and Fortran) |
Number of columns in array |
| mxGetNaN (C and Fortran) |
Value of NaN (Not-a-Number) |
| mxGetNumberOfDimensions (C and Fortran) |
Number of dimensions in array |
| mxGetNumberOfElements (C and Fortran) |
Number of elements in array |
| mxGetNumberOfFields (C and Fortran) |
Number of fields in structure array |
| mxGetNzmax (C and Fortran) |
Number of elements in IR, PR, and PI arrays |
| mxGetPi (C and Fortran) |
Imaginary data elements in array of type DOUBLE |
| mxGetPr (C and Fortran) |
Real data elements in array of type DOUBLE |
| mxGetProperty (C and Fortran) |
Value of public property of MATLAB object |
| mxGetScalar (C and Fortran) |
Real component of first data element in array |
| mxGetString (C and Fortran) |
String array to C-style string |
| mxIsCell (C and Fortran) |
Determine whether input is cell array |
| mxIsChar (C and Fortran) |
Determine whether input is string array |
| mxIsClass (C and Fortran) |
Determine whether array is member of specified class |
| mxIsComplex (C and Fortran) |
Determine whether data is complex |
| mxIsDouble (C and Fortran) |
Determine whether mxArray represents data as double-precision, floating-point numbers |
| mxIsEmpty (C and Fortran) |
Determine whether array is empty |
| mxIsFinite (C and Fortran) |
Determine whether input is finite |
| mxIsFromGlobalWS (C and Fortran) |
Determine whether array was copied from MATLAB global workspace |
| mxIsInf (C and Fortran) |
Determine whether input is infinite |
| mxIsInt16 (C and Fortran) |
Determine whether array represents data as signed 16-bit integers |
| mxIsInt32 (C and Fortran) |
Determine whether array represents data as signed 32-bit integers |
| mxIsInt64 (C and Fortran) |
Determine whether array represents data as signed 64-bit integers |
| mxIsInt8 (C and Fortran) |
Determine whether array represents data as signed 8-bit integers |
| mxIsLogical (C and Fortran) |
Determine whether array is of type mxLogical |
| mxIsLogicalScalar (C) |
Determine whether scalar array is of type mxLogical |
| mxIsLogicalScalarTrue (C) |
Determine whether scalar array of type mxLogical is true |
| mxIsNaN (C and Fortran) |
Determine whether input is NaN (Not-a-Number) |
| mxIsNumeric (C and Fortran) |
Determine whether array is numeric |
| mxIsSingle (C and Fortran) |
Determine whether array represents data as single-precision, floating-point numbers |
| mxIsSparse (C and Fortran) |
Determine whether input is sparse array |
| mxIsStruct (C and Fortran) |
Determine whether input is structure array |
| mxIsUint16 (C and Fortran) |
Determine whether array represents data as unsigned 16-bit integers |
| mxIsUint32 (C and Fortran) |
Determine whether array represents data as unsigned 32-bit integers |
| mxIsUint64 (C and Fortran) |
Determine whether array represents data as unsigned 64-bit integers |
| mxIsUint8 (C and Fortran) |
Determine whether array represents data as unsigned 8-bit integers |
| mxLogical (C) |
Type for logical array |
| mxMalloc (C and Fortran) |
Allocate dynamic memory using MATLAB memory manager |
| mxRealloc (C and Fortran) |
Reallocate dynamic memory using MATLAB memory manager |
| mxRemoveField (C and Fortran) |
Remove field from structure array |
| mxSetCell (C and Fortran) |
Value of one cell of array |
| mxSetClassName (C) |
Convert structure array to MATLAB object array |
| mxSetData (C and Fortran) |
Set pointer to data |
| mxSetDimensions (C and Fortran) |
Modify number of dimensions and size of each dimension |
| mxSetField (C and Fortran) |
Set structure array field, given structure field name and array index |
| mxSetFieldByNumber (C and Fortran) |
Set structure array field, given field number and index |
| mxSetImagData (C and Fortran) |
Imaginary data pointer for array |
| mxSetIr (C and Fortran) |
IR array of sparse array |
| mxSetJc (C and Fortran) |
JC array of sparse array |
| mxSetM (C and Fortran) |
Number of rows in array |
| mxSetN (C and Fortran) |
Set number of columns in array |
| mxSetNzmax (C and Fortran) |
Set storage space for nonzero elements |
| mxSetPi (C and Fortran) |
Set new imaginary data for array |
| mxSetPr (C and Fortran) |
Set new real data for array |
| mxSetProperty (C and Fortran) |
Set value of public property of MATLAB object |
MEX Library
| mexAtExit (C and Fortran) |
Register function to call when MEX-function cleared or MATLAB software terminates |
| mexCallMATLAB (C and Fortran) |
Call MATLAB function, user-defined function, or MEX-file |
| mexCallMATLABWithTrap (C and Fortran) |
Call MATLAB function, user-defined function, or MEX-file and capture error information |
| mexErrMsgIdAndTxt (C and Fortran) |
Display error message with identifier and return to MATLAB prompt |
| mexErrMsgTxt (C and Fortran) |
Display error message and return to MATLAB prompt |
| mexEvalString (C and Fortran) |
Execute MATLAB command in caller workspace |
| mexEvalStringWithTrap (C and Fortran) |
Execute MATLAB command in caller workspace and capture error information |
| mexFunction (C and Fortran) |
Entry point to C/C++ or Fortran MEX-file |
| mexFunctionName (C and Fortran) |
Name of current MEX-function |
| mexGet (C) |
Value of specified Handle Graphics property |
| mexGetVariable (C and Fortran) |
Copy of variable from specified workspace |
| mexGetVariablePtr (C and Fortran) |
Read-only pointer to variable from another workspace |
| mexIsGlobal (C and Fortran) |
Determine whether variable has global scope |
| mexIsLocked (C and Fortran) |
Determine whether MEX-file is locked |
| mexLock (C and Fortran) |
Prevent clearing MEX-file from memory |
| mexMakeArrayPersistent (C and Fortran) |
Make array persist after MEX-file completes |
| mexMakeMemoryPersistent (C and Fortran) |
Make memory allocated by MATLAB software persist after MEX-function completes |
| mexPrintf (C and Fortran) |
ANSI C PRINTF-style output routine |
| mexPutVariable (C and Fortran) |
Array from MEX-function into specified workspace |
| mexSet (C) |
Set value of specified Handle Graphics property |
| mexSetTrapFlag (C and Fortran) |
Control response of MEXCALLMATLAB to errors |
| mexUnlock (C and Fortran) |
Allow clearing MEX-file from memory |
| mexWarnMsgIdAndTxt (C and Fortran) |
Warning message with identifier |
| mexWarnMsgTxt (C and Fortran) |
Warning message |