Usage
stepsize(x, ...)
## S3 method for class 'default':
stepsize(x, ...)
## S3 method for class 'numeric':
stepsize(x, ...)
## S3 method for class 'generic_spct':
stepsize(x, ...)
## S3 method for class 'generic_mspct':
stepsize(x, ..., idx = !is.null(names(x)))