Major rework to improve code quality and add automation checks (#805)

* delete secant method - it is identical to regula falsi

* document + improvize root finding algorithms

* attempt to document gaussian elimination

* added file brief

* commented doxygen-mainpage, added files-list link

* corrected files list link path

* files-list link correction - this time works :)

* document successive approximations

* cleaner equation

* updating DIRECTORY.md

* documented kmp string search

* document brute force string search

* document rabin-karp string search

* fixed mainpage readme

* doxygen v1.8.18 will suppress out the #minipage in the markdown

* cpplint correction for header guard style

* github action to auto format source code per cpplint standard

* updated setting to add 1 space before `private` and `public` keywords

* auto rename files and auto format code

* added missing "run" for step

* corrected asignmemt operation

* fixed trim and assign syntax

* added git move for renaming bad filenames

* added missing pipe for trim

* added missing space

* use old and new fnames

* store old fname using echo

* move files only if there is a change in filename

* put old filenames in quotes

* use double quote for old filename

* escape double quotes

* remove old_fname

* try escape characters and echo"

* add file-type to find

* cleanup echo

* ensure all trim variables are also in quotes

* try escape -quote again

* remove second escpe quote

* use single quote for first check

* use carets instead of quotes

* put variables in brackets

* remove -e from echo

* add debug echos

* try print0 flag

* find command with while instead of for-loop

* find command using IFS instead

* 🎉 IFS fix worked - escaped quotes for git mv

* protetc each word in git mv ..

* filename exists in lower cases - renamed

* 🎉 git push enabled

* updating DIRECTORY.md

* git pull & then push

* formatting filenames d7af6fdc8c

* formatting source-code for d7af6fdc8c

* remove allman break before braces

* updating DIRECTORY.md

* added missing comma lost in previous commit

* orchestrate all workflows

* fix yml indentation

* force push format changes, add title to DIRECTORY.md

* pull before proceeding

* reorganize pull commands

* use master branches for actions

* rename .cc files to .cpp

* added class destructor to clean up dynamic memory allocation

* rename to awesome workflow

* commented whole repo cpplint - added modified files lint check

* removed need for cpplint

* attempt to use actions/checkout@master

* temporary: no dependency on cpplint

* formatting filenames 153fb7b8a5

* formatting source-code for 153fb7b8a5

* updating DIRECTORY.md

* fix diff filename

* added comments to the code

* added test case

* formatting source-code for a850308fba

* updating DIRECTORY.md

* added machine learning folder

* added adaline algorithm

* updating DIRECTORY.md

* fixed issue [LWG2192](https://cplusplus.github.io/LWG/issue2192) for std::abs on MacOS

* add cmath for same bug: [LWG2192](https://cplusplus.github.io/LWG/issue2192) for std::abs on MacOS

* formatting source-code for f8925e4822

* use STL's inner_product

* formatting source-code for f94a330594

* added range comments

* define activation function

* use equal initial weights

* change test2 function to predict

* activation function not friend

* previous commit correction

* added option for predict function to return value before applying activation function as optional argument

* added test case to classify points lying within a sphere

* improve documentation for adaline

* formatting source-code for 15ec4c3aba

* added cmake to geometry folder

* added algorithm include for std::max

* add namespace - machine_learning

* add namespace - statistics

* add namespace - sorting

* added sorting algos to namespace sorting

* added namespace string_search

* formatting source-code for fd69530515

* added documentation to string_search namespace

* feat: Add BFS and DFS algorithms to check for cycle in a directed graph

* Remove const references for input of simple types

Reason: overhead on access

* fix bad code

sorry for force push

* Use pointer instead of the non-const reference

because apparently google says so.

* Remove a useless and possibly bad Graph constuctor overload

* Explicitely specify type of vector during graph instantiation

* updating DIRECTORY.md

* find openMP before adding subdirectories

* added kohonen self organizing map

* updating DIRECTORY.md

* remove older files and folders from gh-pages before adding new files

* remove chronos library due to inacceptability by cpplint

* use c++ specific static_cast instead

* initialize radom number generator

* updated image links with those from CPP repository

* rename computer.... folder to numerical methods

* added durand kerner method for root computation for arbitrarily large polynomials

* fixed additional comma

* fix cpplint errors

* updating DIRECTORY.md

* convert to function module

* update documentation

* move openmp to main loop

* added two test cases

* use INT16_MAX

* remove return statement from omp-for loop and use "break"

* run tests when no input is provided and skip tests when input polynomial is provided

* while loop cannot have break - replaced with continue and check is present in the main while condition

* (1) break while loop (2) skip runs on break_loop instead of hard-break

* add documentation images

* use long double for errors and tolerance checks

* make iterator variable i local to threads

* add critical secions to omp threads

* bugfix: move file writing outside of the parallel loop
othersie, there is no gurantee of the order of roots written to file

* rename folder to data_structures

* updating DIRECTORY.md

* fix ambiguous symbol `size`

* add data_structures to cmake

* docs: enable tree view, add timestamp in footer, try clang assistaed parsing

* doxygen - open links in external window

* remove invalid parameter from function docs

* use HTML5 img tag to resize images

* move file to proper folder

* fix documentations and cpplint

* formatting source-code for aacaf9828c

* updating DIRECTORY.md

* cpplint: add braces for multiple statement if

* add explicit link to badges

* remove  duplicate line

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* remove namespace indentation

* remove file associations in settings

* add author name

* enable cmake in subfolders of data_structures

* create and link object file

* cpp lint fixes and instantiate template classes

* cpp lint fixes and instantiate template classes

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* cpplint - ignore `build/include`

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* disable redundant gcc compilation in cpplint workflow

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* template header files contain function codes as well and removed redundant subfolders

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* updating DIRECTORY.md

* remove semicolons after functions in a class

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* cpplint header guard style

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* remove semilon

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* added LU decomposition algorithm

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* added QR decomposition algorithm

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* use QR decomposition to find eigen values

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* updating DIRECTORY.md

* use std::rand for thread safety

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* move srand to main()

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* cpplint braces correction

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* updated eigen value documentation

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* fix matrix shift doc

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* rename CONTRIBUTION.md to CONTRIBUTING.md #836

* remove 'sort alphabetical order' check

* added documentation check

* remove extra paranthesis

* added gitpod

* added gitpod link from README

* attempt to add vscode gitpod extensions

* update gitpod extensions

* add gitpod extensions cmake-tools and git-graph

* remove gitpod init and add commands

* use init to one time install doxygen, graphviz, cpplint

* use gitpod dockerfile

* add ninja build system to docker

* remove configure task

* add github prebuild specs to gitpod

* disable gitpod addcommit

* update documentation for kohonen_som

* added ode solve using forward euler method

* added mid-point euler ode solver

* fixed itegration step equation

* added semi-implicit euler ODE solver

* updating DIRECTORY.md

* fix cpplint issues - lines 117 and 124

* added documentation to ode group

* corrected semi-implicit euler function

* updated docs and test cases better structure

* replace `free` with `delete` operator

* formatting source-code for f55ab50cf2

* updating DIRECTORY.md

* main function must return

* added machine learning group

* added kohonen som topology algorithm

* fix graph image path

* updating DIRECTORY.md

* fix braces

* use snprintf instead of sprintf

* use static_cast

* hardcode character buffer size

* fix machine learning groups in documentation

* fix missing namespace function

* replace kvedala fork references to TheAlgorithms

* fix bug in counting_sort

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Anmol3299 <mittalanmol22@gmail.com>

strings/rabin_karp.cpp

@@ -1,39 +1,65 @@
-/*
- * file name : rabin_karp.cpp
- * author    : Amit Kumar 
- * Copyright : 2020 , Amit Kumar 
- * version   : 1.0
+/**
+ * \file
+ * \brief The [Rabin-Karp
+ * Algorithm](https://en.wikipedia.org/wiki/Rabin–Karp_algorithm) for finding a
+ * pattern within a piece of text with complexity O(n + m)
  */
-#include<cassert>
-#include<cmath>
-#include<iostream>
-#include<string>
+#include <cassert>
+#include <cmath>
+#include <iostream>
+#ifdef _MSC_VER
+#include <string>  // use this for MS Visucal C++
+#else
+#include <cstring>
+#endif
 
-using std::string;
-using std::pow;
+#define PRIME 5  ///< Prime modulus for hash functions
 
-#define PRIME 5
-
-int64_t create_hash(string s , int n) {
+namespace string_search {
+/**
+ * convert a string to an intger - called as hashing function
+ * \param[in] s source of string to hash
+ * \param[in] n length of substring to hash
+ * \returns hash integer
+ */
+int64_t create_hash(const std::string& s, int n) {
     int64_t result = 0;
-    for ( int i = 0; i < n; ++i ) {
-        result += (int64_t)(s[i] * (int64_t)pow(PRIME , i));
+    for (int i = 0; i < n; ++i) {
+        result += (int64_t)(s[i] * (int64_t)pow(PRIME, i));
     }
     return result;
 }
 
-int64_t recalculate_hash(string s , int old_index ,
-        int new_index , int64_t old_hash , int patLength) {
+/**
+ * re-hash a string using known existing hash
+ * \param[in] s source of string to hash
+ * \param[in] old_index previous index of string
+ * \param[in] new_index new index of string
+ * \param[in] old_hash previous hash of substring
+ * \param[in] patLength length of substring to hash
+ * \returns new hash integer
+ */
+int64_t recalculate_hash(const std::string& s, int old_index, int new_index,
+                         int64_t old_hash, int patLength) {
     int64_t new_hash = old_hash - s[old_index];
     new_hash /= PRIME;
-    new_hash += (int64_t)(s[new_index]*(int64_t)pow(PRIME, patLength-1));
+    new_hash += (int64_t)(s[new_index] * (int64_t)pow(PRIME, patLength - 1));
     return new_hash;
 }
 
-bool check_if_equal(string str1 , string str2 ,
-                    int start1 , int end1 ,
-                    int start2 , int end2) {
-    if (end1-start1 != end2-start2) {
+/**
+ * compare if two sub-strings are equal
+ * \param[in] str1 string pattern to search
+ * \param[in] str2 text in which to search
+ * \param[in] start1,end1 start and end indices for substring in str1
+ * \param[in] start2,end2 start and end indices for substring in str2
+ * \returns `true` if pattern was found
+ * \returns `false` if pattern was not found
+ * @note can this be replaced by std::string::compare?
+ */
+bool check_if_equal(const std::string& str1, const std::string& str2,
+                    int start1, int end1, int start2, int end2) {
+    if (end1 - start1 != end2 - start2) {
         return false;
     }
     while (start1 <= end1 && start2 <= end2) {
@@ -46,33 +72,40 @@ bool check_if_equal(string str1 , string str2 ,
     return true;
 }
 
-/*
- *  @description : search pattern in the given text 
- *  @param : string str
- *  @param : string pat
- *  @return index of first occurrence of pattern or -1 if pattern not found
+/**
+ *  Perform string pattern search using Rabin-Karp algorithm
+ *  @param[in] str string to search in
+ *  @param[in] pat pattern to search for
+ *  @return index of first occurrence of pattern
+ *  @return -1 if pattern not found
  */
 
-int rabin_karp(const string &str , const string& pat) {
-    int64_t pat_hash = create_hash(pat , pat.size());
-    int64_t str_hash = create_hash(str , pat.size());
-    for (int i=0;  i <= str.size()-pat.size(); ++i) {
+int rabin_karp(const std::string& str, const std::string& pat) {
+    int64_t pat_hash = create_hash(pat, pat.size());
+    int64_t str_hash = create_hash(str, pat.size());
+    for (int i = 0; i <= str.size() - pat.size(); ++i) {
         if (pat_hash == str_hash &&
-            check_if_equal(str , pat , i , i+pat.size()-1 , 0 , pat.size()-1)) {
-                return i;
+            check_if_equal(str, pat, i, i + pat.size() - 1, 0,
+                           pat.size() - 1)) {
+            return i;
         }
-        if (i < str.size()-pat.size()) {
+        if (i < str.size() - pat.size()) {
             str_hash =
-                recalculate_hash(str, i, i+pat.size(), str_hash, pat.size());
+                recalculate_hash(str, i, i + pat.size(), str_hash, pat.size());
         }
     }
     return -1;  // return -1 if given pattern not found
 }
 
+}  // namespace string_search
+
+using string_search::rabin_karp;
+
+/** Main function */
 int main(void) {
-    assert(rabin_karp("helloWorld", "world")    == -1);
-    assert(rabin_karp("helloWorld", "World")    ==  5);
-    assert(rabin_karp("this_is_c++" , "c++")   ==  8);
-    assert(rabin_karp("happy_coding", "happy") ==  0);
+    assert(rabin_karp("helloWorld", "world") == -1);
+    assert(rabin_karp("helloWorld", "World") == 5);
+    assert(rabin_karp("this_is_c++", "c++") == 8);
+    assert(rabin_karp("happy_coding", "happy") == 0);
     return 0;
 }