JCublasJava/src/main/java/jcuda/jcublas/JCublas.java
public static double cublasDzasum(int n, Pointer x, int incx)
    {
        double result = cublasDzasumNative(n, x, incx);
        checkResultBLAS();
        return result;
    }
public static double cublasDzasum(int n, Pointer x, int incx)
    {
        double result = cublasDzasumNative(n, x, incx);
        checkResultBLAS();
        return result;
    }
<pre>
double
cublasDzasum (int n, const cuDoubleComplex *x, int incx)

takes the sum of the absolute values of a complex vector and returns a
double precision result. Note that this is not the L1 norm of the vector.
The result is the sum from 0 to n-1 of abs(real(x[ix+i*incx])) +
abs(imag(x(ix+i*incx))), where ix = 1 if incx <= 0, else ix = 1+(1-n)*incx.

Input
-----
n      number of elements in input vector
x      double-complex vector with n elements
incx   storage spacing between elements of x

Output
------
returns the double precision sum of absolute values of real and imaginary
parts (0 if n <= 0 or incx <= 0, or if an error occurs)

Reference: http://www.netlib.org/blas/dzasum.f

Error status for this function can be retrieved via cublasGetError().

Error Status
------------
CUBLAS_STATUS_NOT_INITIALIZED  if CUBLAS library has not been initialized
CUBLAS_STATUS_ARCH_MISMATCH    if invoked on device without DP support
CUBLAS_STATUS_EXECUTION_FAILED if function failed to launch on GPU
</pre>