iFit/std

PURPOSE

SYNOPSIS

DESCRIPTION

 [half_width, center] = std(s, dim) : standard deviation of iData

   @iData/std function to compute the standard deviation of objects, that is
     their gaussian half width (second moment). Optionally, the distribution  
     center (first moment) can be returned as well.
   std(a, dim) computes standard deviation along axis of rank 'dim'.
     When omitted, dim is set to 1.
   std(a, -dim)
     Using a negative dimension will subtract minimum signal value to signal
       before computation of std, that is remove background. This may be
       needed to avoid an imaginary result.
   std(a, 0) computes std(Signal) and mean(Signal).

 input:  a: object or array (iData/array of)
         dim: dimension to use. Negative dim subtract background (int/array)
 output: half_width: standard deviation (scalar/array)
         center:     center of distribution (scalar/array)
 ex:     a=iData(peaks); c=std(a);

 Version: Nov. 26, 2018
 See also iData, iData/median, iData/mean

CROSS-REFERENCE INFORMATION

• abs b = abs(s) : absolute value of iData object
• double d = double(s) : convert iData into doubles
• end b = end(s,index,n) : end value for iData objects
• getaxis [val, lab] = getaxis(s, AxisIndex) : get iData axis value and label
• isempty isempty(s) : true for empty iData object
• isfloat b = isfloat(s) : True for float iData object elements
• isreal b = isreal(s) : True for real iData object elements
• isvector b = isvector(s) : True for vector iData object
• mean b = mean(s, dim) : mean value of iData object
• meshgrid s = meshgrid(a) : transforms an iData object so that its axes are grids
• min [m,id] = min(a,b, dim) : computes the maximum value of iData object(s)
• ndims d = ndims(s) : get the dimensionality of iData object
• sqrt b = sqrt(s) : square root value of iData object
• std [half_width, center] = std(s, dim) : standard deviation of iData
• sum s = sum(a,dim) : computes the sum of iData objects elements

• camproj s = camproj(a,dim) : projection/radial integration of iData objects elements
• cart2sph s = cart2sph(a,dim) : cartesian to polar/spherical representation of iData objects
• disp disp(s) : display iData object (details)
• help c = help(s) : display iData information as a Dialogue window
• kmeans [b,c] = kmeans(X, k) : k-means clustering of iData object
• pca [b] = pca(X, k) : Principal component analysis of iData object(s)
• peaks [half_width, center, amplitude, baseline] = peaks(s, dim, m) : peak position and width of iData
• std [half_width, center] = std(s, dim) : standard deviation of iData