NumPy (numarray) problem with C code

**David M. Cooke** · Jul 18 '05, 09:17 AM

Re: NumPy (numarray) problem with C code

At some point, Marc Schellens <m_schellens@ho tmail.com> wrote:
[color=blue]
> Following the NumPy documentation, I took over some C code,
> but run into an error.
> Does anybody have a suggestion?
> Thanks,
> marc
>
>
> gdlpython.cpp:2 25: `PyArray_Type' undeclared (first use this function)
>
> #include <python2.3/Python.h>
> // python numarray is used
> #include <python2.3/numarray/arrayobject.h>[/color]

I don't know how you're compiling, but you're probably better off
using
#include "Python.h"
#include "numarray/arrayobject.h"

and specifying the proper include directory. This way you're not
hardcoded to the Python version. distutils automatically adds the
proper directory to the compile line, for instance.

You're using numarray, so you may want to use the numarray interface
instead of the Numeric compability interface. Include
"numarray/libnumarray.h" instead of "numarray/arrayobject.h"
[color=blue]
> // ...
>
> BaseGDL* FromPython( PyObject* pyObj)
> {
> PyObject *object;
>
> // following is line 225
> if( !PyArg_ParseTup le(pyObj, "O!", &PyArray_Typ e, &object))[/color]

There is no such thing as PyArray_Type in numarray, and actually,
there isn't one array type. I'd check for the specific
string/long/complex/double types first (your code below)..
[color=blue]
> {
> // non-array - try other
> PyErr_Clear();
> // string
> char* s;
> if( PyArg_ParseTupl e(pyObj, "s", s))
> return new DStringGDL( string(s));
> PyErr_Clear();
> // integer
> DLong l;
> if( PyArg_ParseTupl e(pyObj, "l", &l))
> return new DLongGDL( l);
> PyErr_Clear();
> // complex
> Py_complex c;
> if( PyArg_ParseTupl e(pyObj, "D", &c))
> {
> DComplexDbl cc( c.real, c.imag);
> return new DComplexDblGDL( cc);
> }
> PyErr_Clear();
> // float
> DDouble d;
> if( PyArg_ParseTupl e(pyObj, "d", &d))
> return new DDoubleGDL( d);
>
> throw GDLException( "FromPython : Cannot convert python object.") ;
> }[/color]

and use NA_InputArray() to get the array. This returns NULL if it
can't make the argument an array. You're using the Numeric
compatibility functions below; you might as well use the numarray
equivalents instead.
[color=blue]
> // array type
> PyArrayObject* array = (PyArrayObject* ) object;
>
> int nDim = array->nd;
> int item_type = array->descr->type_num;
>
> // make array contiguous
> // array = static_cast< PyArrayObject*>
> // (PyArray_Contig uousFromObject( object,
> // item_type,
> // 0,0));
> array = (PyArrayObject* ) PyArray_Contigu ousFromObject( object,
> item_type,
> 0,0);
> if( array == NULL)
> throw GDLException( "FromPython : Error making array contiguous.") ;[/color]

Note that array will be NULL also if it's not an array; this would be
a better way to use it.

Replace the above with something like

PyArrayObject* array = NA_InputArray(o bject, tAny, NUM_C_ARRAY);
if (array == NULLL) {
throw GDLException( "FromPython : Error making array contiguous.") ;
}
int item_type = array->descr->type_num;

Double-check the numarray C API documentation as to whether you should use
NA_InputArray or NA_IoArray.

Haven't looked at the following carefully:[color=blue]
> size_t dimArr[ MAXRANK];
> if( nDim > MAXRANK)
> {
> Warning( "FromPython : Array has more than "+MAXRANK_S TR+
> " dimensions. Extending last one.");
> size_t lastDim = array->dimensions[ MAXRANK-1];
> for( size_t i=MAXRANK; i<nDim; ++i) lastDim *= array->dimensions[ i];
> for( size_t i=0; i<MAXRANK-1; ++i)
> dimArr[ i] = array->dimensions[ i];
> dimArr[ MAXRANK-1] = lastDim;
> nDim = MAXRANK;
> }
> else
> {
> for( size_t i=0; i<nDim; ++i)
> dimArr[ i] = array->dimensions[ i];
> }
>
> dimension dim( dimArr, nDim);[/color]

Use the numarray types instead: tUInt8, tInt8, tInt16, tFloat64, etc:
[color=blue]
> switch( item_type)
> {
> // case PyArray_NOTYPE: //UNDEF***
> case PyArray_UBYTE: //BYTE
> return NewFromPyArrayO bject< DByteGDL>( dim, array);
> case PyArray_SHORT: //INT
> return NewFromPyArrayO bject< DIntGDL>( dim, array);
> case PyArray_INT: //LONG
> return NewFromPyArrayO bject< DLongGDL>( dim, array);
> case PyArray_FLOAT: //FLOAT
> return NewFromPyArrayO bject< DFloatGDL>( dim, array);
> case PyArray_DOUBLE: //DOUBLE
> return NewFromPyArrayO bject< DDoubleGDL>( dim, array);
> case PyArray_CFLOAT: //COMPLEX
> return NewFromPyArrayO bject< DComplexGDL>( dim, array);
> // case PyArray_NOTYPE: //STRING***
> // case PyArray_NOTYPE: //STRUCT***
> case PyArray_CDOUBLE : //COMPLEXDBL
> return NewFromPyArrayO bject< DComplexDblGDL> ( dim, array);
> // case PyArray_NOTYPE: //PTR***
> // case PyArray_NOTYPE: //OBJECT***
> case tUInt16: //UINT*
> return NewFromPyArrayO bject< DUIntGDL>( dim, array);
> case tUInt32: //ULONG*
> return NewFromPyArrayO bject< DULongGDL>( dim, array);
> default:
> throw GDLException( "FromPython : Unknown array type.") ;
> }
>
> return NULL; // compiler shut-up
> }[/color]

--
|>|\/|<
/--------------------------------------------------------------------------\
|David M. Cooke
|cookedm(at)phy sics(dot)mcmast er(dot)ca

**Marc Schellens** · Jul 18 '05, 09:18 AM

Re: NumPy (numarray) problem with C code

Thanks,
I think I was using the wrong documentation.
marc

David M. Cooke wrote:[color=blue]
> At some point, Marc Schellens <m_schellens@ho tmail.com> wrote:
>
>[color=green]
>>Following the NumPy documentation, I took over some C code,
>>but run into an error.
>>Does anybody have a suggestion?
>>Thanks,
>>marc
>>
>>
>>gdlpython.cpp :225: `PyArray_Type' undeclared (first use this function)
>>
>>#include <python2.3/Python.h>
>>// python numarray is used
>>#include <python2.3/numarray/arrayobject.h>[/color]
>
>
> I don't know how you're compiling, but you're probably better off
> using
> #include "Python.h"
> #include "numarray/arrayobject.h"
>
> and specifying the proper include directory. This way you're not
> hardcoded to the Python version. distutils automatically adds the
> proper directory to the compile line, for instance.
>
> You're using numarray, so you may want to use the numarray interface
> instead of the Numeric compability interface. Include
> "numarray/libnumarray.h" instead of "numarray/arrayobject.h"
>
>[color=green]
>>// ...
>>
>>BaseGDL* FromPython( PyObject* pyObj)
>>{
>> PyObject *object;
>>
>>// following is line 225
>> if( !PyArg_ParseTup le(pyObj, "O!", &PyArray_Typ e, &object))[/color]
>
>
> There is no such thing as PyArray_Type in numarray, and actually,
> there isn't one array type. I'd check for the specific
> string/long/complex/double types first (your code below)..
>
>[color=green]
>> {
>> // non-array - try other
>> PyErr_Clear();
>> // string
>> char* s;
>> if( PyArg_ParseTupl e(pyObj, "s", s))
>> return new DStringGDL( string(s));
>> PyErr_Clear();
>> // integer
>> DLong l;
>> if( PyArg_ParseTupl e(pyObj, "l", &l))
>> return new DLongGDL( l);
>> PyErr_Clear();
>> // complex
>> Py_complex c;
>> if( PyArg_ParseTupl e(pyObj, "D", &c))
>> {
>> DComplexDbl cc( c.real, c.imag);
>> return new DComplexDblGDL( cc);
>> }
>> PyErr_Clear();
>> // float
>> DDouble d;
>> if( PyArg_ParseTupl e(pyObj, "d", &d))
>> return new DDoubleGDL( d);
>>
>> throw GDLException( "FromPython : Cannot convert python object.") ;
>> }[/color]
>
>
> and use NA_InputArray() to get the array. This returns NULL if it
> can't make the argument an array. You're using the Numeric
> compatibility functions below; you might as well use the numarray
> equivalents instead.
>
>[color=green]
>> // array type
>> PyArrayObject* array = (PyArrayObject* ) object;
>>
>> int nDim = array->nd;
>> int item_type = array->descr->type_num;
>>
>> // make array contiguous
>>// array = static_cast< PyArrayObject*>
>>// (PyArray_Contig uousFromObject( object,
>>// item_type,
>>// 0,0));
>> array = (PyArrayObject* ) PyArray_Contigu ousFromObject( object,
>> item_type,
>> 0,0);
>> if( array == NULL)
>> throw GDLException( "FromPython : Error making array contiguous.") ;[/color]
>
>
> Note that array will be NULL also if it's not an array; this would be
> a better way to use it.
>
> Replace the above with something like
>
> PyArrayObject* array = NA_InputArray(o bject, tAny, NUM_C_ARRAY);
> if (array == NULLL) {
> throw GDLException( "FromPython : Error making array contiguous.") ;
> }
> int item_type = array->descr->type_num;
>
> Double-check the numarray C API documentation as to whether you should use
> NA_InputArray or NA_IoArray.
>
> Haven't looked at the following carefully:
>[color=green]
>> size_t dimArr[ MAXRANK];
>> if( nDim > MAXRANK)
>> {
>> Warning( "FromPython : Array has more than "+MAXRANK_S TR+
>> " dimensions. Extending last one.");
>> size_t lastDim = array->dimensions[ MAXRANK-1];
>> for( size_t i=MAXRANK; i<nDim; ++i) lastDim *= array->dimensions[ i];
>> for( size_t i=0; i<MAXRANK-1; ++i)
>> dimArr[ i] = array->dimensions[ i];
>> dimArr[ MAXRANK-1] = lastDim;
>> nDim = MAXRANK;
>> }
>> else
>> {
>> for( size_t i=0; i<nDim; ++i)
>> dimArr[ i] = array->dimensions[ i];
>> }
>>
>> dimension dim( dimArr, nDim);[/color]
>
>
>
> Use the numarray types instead: tUInt8, tInt8, tInt16, tFloat64, etc:
>
>[color=green]
>> switch( item_type)
>> {
>> // case PyArray_NOTYPE: //UNDEF***
>> case PyArray_UBYTE: //BYTE
>> return NewFromPyArrayO bject< DByteGDL>( dim, array);
>> case PyArray_SHORT: //INT
>> return NewFromPyArrayO bject< DIntGDL>( dim, array);
>> case PyArray_INT: //LONG
>> return NewFromPyArrayO bject< DLongGDL>( dim, array);
>> case PyArray_FLOAT: //FLOAT
>> return NewFromPyArrayO bject< DFloatGDL>( dim, array);
>> case PyArray_DOUBLE: //DOUBLE
>> return NewFromPyArrayO bject< DDoubleGDL>( dim, array);
>> case PyArray_CFLOAT: //COMPLEX
>> return NewFromPyArrayO bject< DComplexGDL>( dim, array);
>> // case PyArray_NOTYPE: //STRING***
>> // case PyArray_NOTYPE: //STRUCT***
>> case PyArray_CDOUBLE : //COMPLEXDBL
>> return NewFromPyArrayO bject< DComplexDblGDL> ( dim, array);
>> // case PyArray_NOTYPE: //PTR***
>> // case PyArray_NOTYPE: //OBJECT***
>> case tUInt16: //UINT*
>> return NewFromPyArrayO bject< DUIntGDL>( dim, array);
>> case tUInt32: //ULONG*
>> return NewFromPyArrayO bject< DULongGDL>( dim, array);
>> default:
>> throw GDLException( "FromPython : Unknown array type.") ;
>> }
>>
>> return NULL; // compiler shut-up
>>}[/color]
>
>[/color]

NumPy (numarray) problem with C code

NumPy (numarray) problem with C code

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