R/pAndwHelperFn.R

In krahim/multitaperDevelopment: multitaperDevelopment

##Helper function's used in P and W (1993) lisp source code 
################################################################################
##library(bitops)

## getNDFT <- function(nNonZeroFreq, sampleSize) {
##    if(is.character(nNonZeroFreq)) {
##       return (switch(tolower(nNonZeroFreq),
##                   "halfnextpowerof2" =  nextPowerOf2(sampleSize),
##                   "nextpowerof2" =  2*nextPowerOf2(sampleSize),
##                   "twicenextpowerof2" =  4*nextPowerOf2(sampleSize),
##                   "fourier" = sampleSize));
##    }
##    if(is.numeric(nNonZeroFreq) &&
##                   powerOf2(nNonZeroFreq) &&
##                   2*nNonZeroFreq >= sampleSize) {
##       return(2*nNonZeroFreq);
##    }
##    return();
## }

## getNFreqs <- function(nNonZeroFreq, sampleSize, returnEstFor0FreqP) {
##    if(!is.logical(returnEstFor0FreqP)) {
##       return();
##    }
##    if(returnEstFor0FreqP) {
##       return(1+ getNDFT(nNonZeroFreq, sampleSize) %/% 2);
##    }
##    return(getNDFT(nNonZeroFreq, sampleSize) %/% 2);
## }

## convertTodB <- function(X) {
##    if(!identical(X[X<=0], numeric(0))) {
##       return();
##    }
##    return(10*log10(X));
## }

## convertFromdB <- function(X) {
##    return(10^(X/10));
## }

##library(bitops)

## powerOf2 <- function(x) {
##    if(as.integer(x)!=x) {
##       return();
##    }
##    if(bitAnd(x,x-1) == 0) {
##       return(log2(x));
##    }
##    else {
##       return();
##    }
## }

## nextPowerOf2 <- function(x) {
##    return(2^(ceiling(log2(x))));
## }

## NyquistFrequency  <- function(sampleTime) {
##    return(1/(2*sampleTime));
## }

## sampleTime <- function(NyquistFrequency) {
##    return(1/(2*NyquistFrequency));
## }