DSPL-2.0 data types.

Macros
#define	RE(x)   (x[0])
	Macro sets real part of the complex number. More...
#define	IM(x)   (x[1])
	Macro sets imaginary part of the complex number. More...
#define	ABSSQR(x)   ((SQR(RE(x))) + (SQR(IM(x))))
	The macro returns the square of the modulus of a complex number x. More...

Typedefs
typedef double	complex_t[2]
	Complex data type. More...

Functions
int DSPL_API	cmplx2re (complex_t *x, int n, double *re, double *im)
	Separate complex vector to the real and image vectors. More...
int DSPL_API	re2cmplx (double *x, int n, complex_t *y)
	Convert real array to the complex array. More...

Detailed Description

This group describes DSPL-2.0 data types and functions and macros for data types conversion.

Macro Definition Documentation

ABSSQR

#define ABSSQR

(

x

)

((SQR(RE(x))) + (SQR(IM(x))))

The macro returns the square of the modulus of a complex number x.

---

Square of the modulus of a complex number \( x = a + j b \) equals:

\[ |x|^2 = x x^* = a^2 + b^2. \]

Example:

complex_t z;
double y;
RE(z) =  1.0;
IM(z) = -2.0;
y = ABSSQR(z);

Variable z = 1-2j, here j - imaginary unit, but variable y = 5.

Definition at line 534 of file dspl.h.

IM

#define IM

(

x

)

(x[1])

Macro sets imaginary part of the complex number.

---

Example:

complex_t z;
RE(z) =  1.0;
IM(z) = -2.0;

Variable z = 1-2j, here j - imaginary unit.

This macro can be used to return imaginary part of the complex number:

complex_t z = {3.0, -4.0};
double    r;
r = IM(z);

In this example z = 3-4i, but variable r will keep -4.

Definition at line 478 of file dspl.h.

RE

#define RE

(

x

)

(x[0])

Macro sets real part of the complex number.

---

Example:

complex_t z;
RE(z) =  1.0;
IM(z) = -2.0;

Variable z = 1-2j, here j - imaginary unit.

This macro can be used to return real part of the complex number:

complex_t z = {3.0, -4.0};
double    r;
r = RE(z);

In this example z = 3-4i, but variable r will keep 3.

Definition at line 420 of file dspl.h.

Typedef Documentation

complex_t

complex_t

Complex data type.

---

libdspl-2.0 describes complex numbers data type as an array of two double elements. First element sets real part, second — imaginary part.

For example:

complex_t z;
z[0] =  1.0;
z[1] = -2.0;

Variable z = 1-2j, here j - imaginary unit.

For the convenience of working with complex numbers implemented special macros: RE, IM, ABSSQR

Definition at line 86 of file dspl.h.

Function Documentation

cmplx2re()

int cmplx2re	(	complex_t *	x,
		int	n,
		double *	re,
		double *	im
	)

Separate complex vector to the real and image vectors.

---

Function fills re and im vectors corresponds to real and image parts of the input complex array x.

Parameters

[in]	x	Pointer to the real complex vector. Vector size is [n x 1].
[in]	n	Size of the input complex vector x and real and image vectors re and im.
[out]	re	Pointer to the real part vector. Vector size is [n x 1]. Memory must be allocated.
[out]	im	Pointer to the image part vector. Vector size is [n x 1]. Memory must be allocated.

Returns

RES_OK if function converts complex vector successfully.
Else code error.
Example:

complex_t x[3] = {{1.0, 2.0}, {3.0, 4.0}, {5.0, 6.0}};
double  re[3], im[3];
 
cmplx2re(x, 3, re, im);

Vectors re and im will contains:

re[0] = 1.0; im[0] = 2.0;
re[1] = 3.0; im[1] = 4.0;
re[2] = 5.0; im[2] = 6.0;

Author

Sergey Bakhurin. www.dsplib.org

Definition at line 130 of file cmplx2re.c.

Referenced by conv_fft(), and xcorr().

re2cmplx()

int re2cmplx	(	double *	x,
		int	n,
		complex_t *	y
	)

Convert real array to the complex array.

---

Function copies the vector x to the real part of vector y. Image part of the vector y sets as zero.
So complex vector contains data:
y[i] = x[i] + j0, here i = 0,1,2 ... n-1

Parameters

[in]	x	Pointer to the real vector x. Vector size is [n x 1].
[in]	n	Size of the real vector x and complex vector y.
[out]	y	Pointer to the complex vector y. Vector size is [n x 1]. Memory must be allocated.

Returns

RES_OK if function returns successfully.
Else code error:
Example:

double x[3] = {1.0, 2.0, 3.0};
complex_t y[3];
 
re2cmplx(x, 3, y);

Vector y will keep:

    y[0] = 1+0j;
    y[1] = 2+0j;
    y[2] = 3+0j.

Author

Sergey Bakhurin. www.dsplib.org

Definition at line 120 of file re2cmplx.c.

Referenced by conv_fft(), fft(), freqs(), freqz(), and xcorr().