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NMRPipe Processing Functions
DX: Derivative by Central Difference.
**

**DX** performs a numerical derivative calculation
on each vector. If the current dimension is complex, the real
and imaginary parts are treated separately. For an N-point data vector
y[0] ... y[N-1] the derivative dy[i] is calculated as:

dy[0] = y[1] - y[0]for the first point.

dy[i] = y[i+1] - y[i-1]for the interior points, and

dy[N] = y[N] - y[N-1]for the last point.

The nmrPipe function INTEG performs
the numerical integral function, the complementary function to
**DX.**