/*
* Find k-mismatches naively.
* @param text A character array containing the text
* @param pattern A character array containing the pattern
* @param n the length of the text
* @param m the length of the pattern
* @param k The threshold, k. If k < 0 or >= m hamming distance at all
* alignments will be found
* @param numMatches an unsigned pointer to a location to store the number
* of k-mismatches found. Note that if k < 0 or >= m this is just n-m.
*/
void sp_km_naive_kmismatch(char *text, char *pattern, int n, int m,int k,
int *numMatches, struct SP_KM_MATCHING_POSITIONS *listOfMatches, unsigned int flags){
int i,j;
if( k < 0){
k = m+1;
}
*numMatches = 0;
for(i=0;i<n-m+1;i++){
int hamDistance = 0;
for(j=0;j<m;j++){
if(text[i+j] != pattern[j]){
hamDistance++;
//If hamming distance is greater than k, we dont need to bother
//computing this anymore
if(hamDistance > k){
break;
}
}
}
if(hamDistance <= k){
(*numMatches)++;
if(listOfMatches!=NULL){
sp_km_addToListOfMatches(listOfMatches,i,hamDistance);
}else{
printf("Hamming distance at text[%d]: %d\n",i,hamDistance);
}
if(flags & SP_KM_FIRST_MATCH_ONLY){
return;
}
}
}
}
/**
* Find the mismatches without filtering. This is the complete method in the case where
* the complexity is unbounded by k, but only applies in one case in the bounded method.
* @TODO: Move this elsewhere; it doesn't apply just to unbounded. Perhaps the same for the above
* @param text A character array containing the text
* @param pattern A character array containing the pattern
* @param n the length of the text
* @param m the length of the pattern
* @param k The threshold, k. If k < 0 or >= m hamming distance at all
* alignments will be found
* @param results. An unsigned array to store the hamming distance in. Must be
* of size n-m+1. If NULL, results are printed to stdout.
* @param numMatches an unsigned pointer to a location to store the number
* of k-mismatches found. Note that if k < 0 or >= m this is just n-m.
* @param sortedPattern. An array of charAndPosition structs, that is sorted but contain
* indices of original location in the pattern
* @param positionLookup. An int array of indexes into the sortedPattern saying where to find
* the start of infrequent characters, or NOT_IN_PATTERN or FREQUENT_CHAR.
*/
void findMismatchesWithoutFiltering(char *text, char *pattern, int n, int m,int k,
int *numMatches,struct SP_KM_MATCHING_POSITIONS *listOfMatches,unsigned flags,
struct charAndPosition *sortedPattern,struct position *positionLookup){
int i;
int transformSize = 2*m;
if(transformSize < 2048 && n > 4096){
transformSize = 2048;
}
//Use double as we will compute Fourier Transform of this
double *maskedPattern = (double *)fftw_malloc(sizeof(double)*transformSize);
//Zero the top "half" of the masked pattern -- this will never be touched
for(i=m;i<transformSize;i++){
maskedPattern[i] = 0.0;
}
//Repeat for text, except we mask potential "overflow" of chunks past n
int overflowed = n + (transformSize - m);
double *maskedText = (double *)fftw_malloc(sizeof(double)*overflowed);
for(i=n;i<overflowed;i++){
maskedText[i] = 0.0;
}
//We will re-use plans across multiple masked patterns, so define these here
fftw_plan forward = NULL;
fftw_plan inverse =NULL;
if(!fftw_import_system_wisdom()){
printf("Failed to read system wisdom!\n");
}
//Create an array that we will use to add matches for each character at
//each alignment
int *matches = (int *) calloc(n-m+1,sizeof(int));
int positionInPattern;
short charType;
int numFFTMatches = 0;
double numInfrequentComparisons = 0.0;
for(i=0;i<n;i++){
charType = positionLookup[(int)text[i]].charType;
positionInPattern = positionLookup[(int)text[i]].index;
if(charType==FREQUENT_CHAR){
maskTextAndPattern(text,pattern,n,m,maskedText,maskedPattern,text[i]);
printf("Frequent char %c\n",text[i]);
computeNumMatchesWithFFT(maskedText,maskedPattern,n,m,transformSize,matches,&forward,&inverse);
numFFTMatches++;
//This will compute matches for ALL of the same character in the text, so now mark this as not occuring in the pattern
positionLookup[(int)text[i]].charType=NOT_IN_PATTERN;
}else if(charType ==INFREQUENT_CHAR){
//printf("Infrequent char %c\n",text[i]);
//Loop though all of the up to O(threshold) characters that are infrequent
while(positionInPattern < m && sortedPattern[positionInPattern].index <= i && sortedPattern[positionInPattern].c == text[i]){
// printf("i-sortedPattern[positionInPattern].index+1: %d\n",i-sortedPattern[positionInPattern].index+1);
// printf("i: %d\n",i);
// printf("sortedPattern[positionInPattern].index: %d\n",sortedPattern[positionInPattern].index);
if(i-sortedPattern[positionInPattern].index < n-m+1){
matches[i-sortedPattern[positionInPattern].index]++;
}
positionInPattern++;
numInfrequentComparisons++;
}
}
}
//printf("Calculated %d matches using Fourier Transforms\n",numFFTMatches);
//printf("Performed %d (*c) comparisons for infrequent characters\n",(int)numInfrequentComparisons);
//We now have matches, so we can compute (and output if necessary) mis-matches
int hamDistance;
for(i=0;i<n-m+1;i++){
hamDistance = m - matches[i];
if(hamDistance <= k){
(*numMatches)++;
if(listOfMatches!=NULL){
sp_km_addToListOfMatches(listOfMatches,i,hamDistance);
}else{
printf("Hamming distance at text[%d]: %d\n",i,hamDistance);
}
if(flags & SP_KM_FIRST_MATCH_ONLY){
return;
}
}
}
done();
free(matches);
fftw_free(maskedPattern);
fftw_free(maskedText);
fftw_destroy_plan(forward);
fftw_destroy_plan(inverse);
fftw_forget_wisdom();
fftw_cleanup();
}
