C / C++ / MFC

Quote:

if m > n, those codes generate U' x U = E (correct), but U' x U != E (error).

if m > n, those codes generate U' x U = E (correct), but U x U' != E (error).

double doubleValue = integerValue;

Vaclav_Sal wrote:

So casting is a bad idea?

Vaclav_Sal wrote:

What exactly is the difference between cast and redefinition?

Vaclav_Sal wrote:

I pass a pointer to this int array either by redefining it as double or as a cast.

int integerValue = 233;
double doubleValue = integerValue; // the integer value is converted to a double
                                   // and stored in the new variable

// the value passed in is already a double, or if not it will be converted
function( doublevalue,... 

// the integer value will be converted into a double. But you do not need a cast.
function( (double) integerValue,.... 

double function(int* myArrayOfIntegers, int count)
{
    double result = 0.0;

    for (int i = 0; i < count; ++i)
    {
        double temp = myArrayOfIntegers[i]; // get next integer and convert to double
        // do some calculations
    }
    return result;
}
// ....

// create an array to hold all the values
int* theIntegers = new int[theCount];
// fill the array from the source values
// ...

// send the array to be processed
double theAnswer = function(theIntegers, theCount);

Vaclav_Sal wrote:

this is getting really interesting.

Vaclav_Sal wrote:

one collecting 10 bits of data into 16 bits integer array

Vaclav_Sal wrote:

if I cast or build a new variable as double it will take an 16 bit integer and
process it as double, than what will happen to the original array ?

Vaclav_Sal wrote:

I am still learning about FFT , but as far as I can tell the first FFT function
puts new data (normal pointer behavior)   into the original (integer )
array as what ? Integer?

Vaclav_Sal wrote:

I think the   only way is to collect the ADC data into double array
from get go.