I made test code for my arduino to begin moving values across the screen. At the bottom of the code [int n+1 = n;], it gives the described error. Is there a good solution for this problem? Thanks.
#include <LiquidCrystal.h>
LiquidCrystal lcd(12,11,5,4,3,2);
int bPin = 6;
int wPin = 7;
int wTime = 30;
int bTime = 30;
int wState =0;
int bState=0;
int n = 0;
void setup(){
lcd.begin(16,2);
pinMode(bPin,INPUT);
pinMode(wPin,INPUT);
lcd.print("Ready?");
}
void loop(){
wState = digitalRead(bPin);
bState = digitalRead(wPin);
lcd.clear();
lcd.setCursor(0,n);
lcd.print("1");
lcd.setCursor(0,n+1);
lcd.print("2");
int n+1 = n;
delay(100);
}
error: expected initializer before '+' token
I think the line
int n+1 = n;
should read
int n = n+1;
Since n is already declared as a global variable in the top of your file, you should simply replace the line:
int n+1 = n;
with:
n += 1;
Related
I'm making an Arduino reverse stopwatch..but Seems to have a problem with millis() function
Whenever I upload the code on Arduino the millis starts running itself..how can I keep it at 0 until I call the millis. or any alternatives to solve it...
#include "SevSeg.h"
int button1 = 11;
int button2 = 12;
int button3 = 13;
int value = 10;
int timer = 0;
bool n = true;
SevSeg Display;
void setup() {
Serial.begin(9600);
byte numDigits = 2;
byte digitPins[] = {9,8};
byte segmentPins[] = {10,2, 3, 4, 5, 6, 7,1};
bool resistorsOnSegments = true;
bool updateWithDelays = true;
byte hardwareConfig = COMMON_ANODE;
Display.begin(hardwareConfig, numDigits, digitPins, segmentPins, resistorsOnSegments);
Display.setBrightness(100);
}
void loop() {
Display.setNumber(value, 1);
Display.refreshDisplay();
if (digitalRead(11)==HIGH){
Start(value);
}
}
void Start(int value){
while(n){
unsigned long timerGlobal = millis();
Display.setNumber(value-timerGlobal/1000, 1);
Display.refreshDisplay();
if ((value-timerGlobal/1000) == 0){
n = false;
}
}
}
In arduino UNO
extern volatile unsigned long timer0_millis;
noInterrupts ();
timer0_millis = 0;
interrupts ();
But it makes no sense at all.
Simply remember the previous millis and calculate time passed (by substracting).
This should work
//#include "SevSeg.h"
int button1 = 11;
int button2 = 12;
int button3 = 13;
int value = 10;
int timer = 0;
bool n = true;
//Added
int currentTime = 0;
long int t0 = 0;
long int t1 = 0;
//SevSeg Display;
void setup() {
Serial.begin(9600);
byte numDigits = 2;
byte digitPins[] = {9,8};
byte segmentPins[] = {10,2, 3, 4, 5, 6, 7,1};
bool resistorsOnSegments = true;
bool updateWithDelays = true;
//byte hardwareConfig = COMMON_ANODE;
//Display.begin(hardwareConfig, numDigits, digitPins, segmentPins, resistorsOnSegments);
//Display.setBrightness(100);
}
void loop() {
//Display.setNumber(value, 1);
// Display.refreshDisplay();
if (digitalRead(11)==HIGH){
Start(value);
}
}
void Start(int value){
t0 = millis();
while(n){
t1 = millis();
if(t1 > (1000+t0)){
//has passed 1 second
currentTime++;
if(value-currentTime == 0){
n = false;
}
}
unsigned long timerGlobal = t1-t0;
//Display.setNumber(value-timerGlobal/1000, 1);
//Display.refreshDisplay();
}
}
Just implement a function that subtract the current millis from the previous millis()
The arduino millis() function is not a function that starts a timer. The millis function is meant to get the elapsed milliseconds since the program started.
Keep in mind that the millis() value will overflow afther:
50 days and 70 minutes. so afther this time the millis() will return 0 again and start over again.
You could implement your own timer using interrupts on the arduino. But like a good programmer always say's if something already exits why make it again? just use the millis() and subtract the current from the previous. But keep in mind of the overflow.
I want to use MPI_Reduce function find largest value and its PID(rank) at the same time, but the result shows it is not true, I don't know how to fix it, result:
PID:1, loc_num:2
PID:2, loc_num:3
PID:3, loc_num:4
global data: 1
coresponding PID: 0
my program:
#include <stdio.h>
#include <string.h>
#include <mpi.h>
int main(int argc, char *argv[])
{
//init MPI
int PID, P;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &P);
MPI_Comm_rank(MPI_COMM_WORLD, &PID);
struct{
int value;
int PID;
} in, out;
int value = 1;
in.value = value;
in.PID = PID;
for(int i = 1; i <= P; i++){
if (PID == i){
value = value + i;
printf("PID:%d, loc_num:%d \n",PID, value);
}
}
MPI_Reduce(&in, &out, 1, MPI_2INT, MPI_MAXLOC, 0, MPI_COMM_WORLD);
int max_PID = out.PID;
int max_num = out.value;
if (PID == 0){
printf("global data: %d \n", max_num);
printf("coresponding PID: %d \n",max_PID);
}
MPI_Finalize();
return 0;
}
I just follow the structure of in.value= value and in.PID=PID and then,every PID calculate value=value+PID so the answer is when PID=1, loc=2;when PID=2, loc=3 ...next compare all of them by max, and sent them to PID=0
There is no error in the MPI_Reduce of your example. As #Gilles pointed out, the issue is you are not assigning the newly calculated value to in.value.
If you put the assignment statement after calculation as below, then everything work as expected.
for(int i = 1; i <= P; i++){
if (PID == i){
value = value + i;
printf("PID:%d, loc_num:%d \n",PID, value);
}
}
in.value = value;
in.PID = PID;
MPI_Reduce(&in, &out, 1, MPI_2INT, MPI_MAXLOC, 0, MPI_COMM_WORLD);
In your example below, you are not assigning the calculated values to the in struct object.
in.value = value; // value is set as 1
in.PID = PID;
for(int i = 1; i <= P; i++){
if (PID == i){
value = value + i; // calculating the value but not assigning to in.value
printf("PID:%d, loc_num:%d \n",PID, value);
}
}
// uses the old value for in.value (i.e 1) for reduction
MPI_Reduce(&in, &out, 1, MPI_2INT, MPI_MAXLOC, 0, MPI_COMM_WORLD);
I need to implement a Rc4 algorithm with a seed: 1 2 3 6 and the plain text cryptology. I am following this guideline we were provided in class, but it's not initializing S correctly.
my output is
and needs to be
My code was previously printing negative values , not sure why but I managed to fix that error. Thought everything was good to go but it's not. Sorry for the pictures, I figured it was easier to explain what I was following for my code structure. I am mod 4 the seed since it contains 4 characters, could that possibly be my error?
#include <iostream>
#include <string>
#include <string.h>
using std::endl;
using std::string;
void swap(unsigned int *x, unsigned int *y);
int main()
{
string plaintext = "cryptology";
char cipherText[256] = { ' ' };
unsigned int S[256] = { 0 };
unsigned int t[256] = { 0 };
unsigned int seed[4] = { 1, 2, 3, 6 }; // seed used for test case 1
unsigned int temp = 0;
int runningTotal = 0;
unsigned int key = 0;
// inilializing s and t
for (int i = 0; i < 256; i++)
{
S[i] = i;
t[i] = seed[i % 4];
}
for (int i = 0; i < 256; i++)
{
runningTotal += S[i] + t[i];
runningTotal %= 256;
swap(&S[runningTotal], &S[i]);
std::cout << S[i] <<" ";
}
runningTotal = 0;
for (int i = 0; i < plaintext.size(); i++)
{
runningTotal %= 256;
swap(&S[i], &S[runningTotal]);
temp = (unsigned int)S[i] + (unsigned int)S[runningTotal];
temp %= 256;
key = S[temp];
std::cout << endl;
cipherText[i] = plaintext[i] ^ key;
}
std::cout << " this is cipher text " << endl;
std::cout << cipherText << endl;
system("pause");
return 0;
}
void swap(unsigned int *x, unsigned int *y)
{
unsigned int temp = 0;
temp = *x;
*x = *y;
*y = temp;
}
Actually I think you're generating S[] correctly. I can only assume you're supposed to do something different with the key. (Perhaps's its an ASCII string instead of four byte values? Check your assignment notes.)
There is a problem later on, however. In the stream generation loop, you're supposed to do the increment and swap operations before you fetch a byte from S[].
for (int k = 0; k < plaintext.size(); k++)
{
i = (i+1) % 256; // increment S[] index
runningTotal = (runningTotal + S[i]) % 256; // swap bytes
swap(&S[i], &S[runningTotal]);
temp = (S[i] + S[runningTotal]) % 256; // fetch byte from S and
cipherText[k] = plaintext[k] ^ S[temp]; // XOR with plaintext
}
NOTE: Although unrelated to your question, your code could be made a lot tidier by using unsigned char values instead of ints. That would eliminate the % 256 instructions that are littered all over the place. (But be careful during initialization, because i<256 will always be true if i is an unsigned char.)
I'm trying to convert a HEX color code to RGB but when I run the code on Arduino, it doesn't pick up the RED.
Am I doing something wrong?
On a C++ compilator works just fine.
void setup() {
Serial.begin(115200);
String hexstring = "B787B7";
int number = (int) strtol( &hexstring[1], NULL, 16);
int r = number >> 16;
int g = number >> 8 & 0xFF;
int b = number & 0xFF;
Serial.print("red is ");
Serial.println(r);
Serial.print("green is ");
Serial.println(g);
Serial.print("blue is ");
Serial.println(b);
}
void loop() {
}
When I ran your code I still was not picking up red's value.
However using MAC's same code
long number = (long) strtol( &hexstring[1], NULL, 16 );
to
long number = (long) strtol( &hexstring[0], NULL, 16 );
I hope this helps someone struggling with RGB and HEX values
Your number should be of type long as type int is coded on 16 bits and cannot take value above 32,767.
void setup() {
Serial.begin(115200);
String hexstring = "B787B7";
long number = (long) strtol( &hexstring[1], NULL, 16);
int r = number >> 16;
int g = number >> 8 & 0xFF;
int b = number & 0xFF;
Serial.print("red is ");
Serial.println(r);
Serial.print("green is ");
Serial.println(g);
Serial.print("blue is ");
Serial.println(b);
}
void loop() {
}
So, my assignment is to write a spell check program and then parallelize it using openMPI. My take was to load the words from a text file into my array called dict[] and this is used as my dictionary. Next, I get input from the user and then it's supposed go through the dictionary array and check whether the current word is within the threshold percentage, if it is, print it out. But I'm only supposed to print out a certain amount of words. My problem is, is that, my suggestions[] array, doesn't seem to fill up the way I need it to, and it gets a lot of blank spots in it, whereas, I thought at least, is that the way I wrote it, is to just fill it when a word is within threshold. So it shouldn't get any blanks in it until there are no more words being added. I think it's close to being finished but I can't seem to figure this part out. Any help is appreciated.
#include <stdio.h>
#include <mpi.h>
#include <string.h>
#include <stdlib.h>
#define SIZE 30
#define max(x,y) (((x) > (y)) ? (x) : (y))
char *dict[50000];
char *suggestions[50000];
char enterWord[50];
char *myWord;
int wordsToPrint = 20;
int threshold = 40;
int i;
int words_added = 0;
int levenshtein(const char *word1, int len1, const char *word2, int len2){
int matrix[len1 + 1][len2 + 1];
int a;
for(a=0; a<= len1; a++){
matrix[a][0] = a;
}
for(a=0;a<=len2;a++){
matrix[0][a] = a;
}
for(a = 1; a <= len1; a++){
int j;
char c1;
c1 = word1[a-1];
for(j = 1; j <= len2; j++){
char c2;
c2 = word2[j-1];
if(c1 == c2){
matrix[a][j] = matrix[a-1][j-1];
}
else{
int delete, insert, substitute, minimum;
delete = matrix[a-1][j] +1;
insert = matrix[a][j-1] +1;
substitute = matrix[a-1][j-1] +1;
minimum = delete;
if(insert < minimum){
minimum = insert;
}
if(substitute < minimum){
minimum = substitute;
}
matrix[a][j] = minimum;
}//else
}//for
}//for
return matrix[len1][len2];
}//levenshtein
void prompt(){
printf("Enter word to search for: \n");
scanf("%s", &enterWord);
}
int p0_compute_output(int num_processes, char *word1){
int totalNumber = 0;
int k = 0;
int chunk = 50000 / num_processes;
for(i = 0; i < chunk; i++){
int minedits = levenshtein(word1, strlen(word1), dict[i], strlen(dict[i]));
int thresholdPercentage = (100 * minedits) / max(strlen(word1), strlen(dict[i]));
if(thresholdPercentage < threshold){
suggestions[totalNumber] = dict[i];
totalNumber = totalNumber + 1;
}
}//for
return totalNumber;
}//p0_compute_output
void p0_receive_output(int next_addition){
int num_to_add;
MPI_Comm comm;
MPI_Status status;
MPI_Recv(&num_to_add,1,MPI_INT,MPI_ANY_SOURCE, MPI_ANY_TAG,MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("--%d\n", num_to_add);
suggestions[next_addition] = dict[num_to_add];
next_addition = next_addition + 1;
}
void compute_output(int num_processes, int me, char *word1){
int chunk = 0;
int last_chunk = 0;
MPI_Comm comm;
if(50000 % num_processes == 0){
chunk = 50000 / num_processes;
last_chunk = chunk;
int start = me * chunk;
int end = me * chunk + chunk;
for(i = start; i < end;i++){
int minedits = levenshtein(word1, strlen(word1), dict[i], strlen(dict[i]));
int thresholdPercentage = (100 * minedits) / max(strlen(word1), strlen(dict[i]));
if(thresholdPercentage < threshold){
int number_to_send = i;
MPI_Send(&number_to_send, 1, MPI_INT, 0, 1, MPI_COMM_WORLD);
}
}
}
else{
chunk = 50000 / num_processes;
last_chunk = 50000 - ((num_processes - 1) * chunk);
if(me != num_processes){
int start = me * chunk;
int end = me * chunk + chunk;
for(i = start; i < end; i++){
int minedits = levenshtein(word1, strlen(word1), dict[i], strlen(dict[i]));
int thresholdPercentage = (100 * minedits) / max(strlen(word1), strlen(dict[i]));
if(thresholdPercentage < threshold){
int number_to_send = i;
MPI_Send(&number_to_send, 1, MPI_INT, 0, 1, MPI_COMM_WORLD);
}//if
}//for
}//if me != num_processes
else{
int start = me * chunk;
int end = 50000 - start;
for(i = start; i < end; i++){
int minedits = levenshtein(word1, strlen(word1), dict[i], strlen(dict[i]));
int thresholdPercentage = (100 * minedits) / max(strlen(word1), strlen(dict[i]));
if(thresholdPercentage < threshold){
int number_to_send = i;
MPI_Send(&number_to_send, 1, MPI_INT, 0, 1, MPI_COMM_WORLD);
}
}
}//me == num_processes
}//BIG else
return;
}//COMPUTE OUTPUT
void set_data(){
prompt();
MPI_Bcast(&enterWord,20 ,MPI_CHAR, 0, MPI_COMM_WORLD);
}//p0_send_inpui
//--------------------------MAIN-----------------------------//
main(int argc, char **argv){
int ierr, num_procs, my_id, loop;
FILE *myFile;
loop = 0;
for(i=0;i<50000;i++){
suggestions[i] = calloc(SIZE, sizeof(char));
}
ierr = MPI_Init(NULL, NULL);
ierr = MPI_Comm_rank(MPI_COMM_WORLD, &my_id);
ierr = MPI_Comm_size(MPI_COMM_WORLD, &num_procs);
printf("Check in from %d of %d processors\n", my_id, num_procs);
set_data();
myWord = enterWord;
myFile = fopen("words", "r");
if(myFile != NULL){
for(i=0;i<50000;i++){
dict[i] = calloc(SIZE, sizeof(char));
fscanf(myFile, "%s", dict[i]);
}//for
fclose(myFile);
}//read word list into dictionary
else printf("File not found");
if(my_id == 0){
words_added = p0_compute_output(num_procs, enterWord);
printf("words added so far: %d\n", words_added);
p0_receive_output(words_added);
printf("Threshold: %d\nWords To print: %d\n%s\n", threshold, wordsToPrint, myWord);
ierr = MPI_Finalize();
}
else{
printf("my word %s*\n", enterWord);
compute_output(num_procs, my_id, enterWord);
// printf("Process %d terminating...\n", my_id);
ierr = MPI_Finalize();
}
for(i=0;i<wordsToPrint;i++){
printf("*%s\n", suggestions[i]);
}//print suggestions
return (0);
}//END MAIN
Here are a few problems I see with what you're doing:
prompt() should only be called by rank 0.
The dictionary file should be read only by rank 0, then broadcast the array out to the other ranks
Alternatively, have rank 1 read the file while rank 0 is waiting for input, broadcast input and dictionary afterwards.
You're making the compute_output step overly complex. You can merge p0_compute_output and compute_output into one routine.
Store an array of indices into dict in each rank
This array will not be the same size in every rank, so the simplest way to do this would be to send from each rank a single integer indicating the size of the array, then send the array with this size. (The receiving rank must know how much data to expect). You could also use the sizes for MPI_Gatherv, but I expect this is more than you're wanting to do right now.
Once you have a single array of indices in rank 0, then use this to fill suggestions.
Save the MPI_Finalize call until immediately before the return call
For the final printf call, only rank 0 should be printing that. I suspect this is causing a large part of the "incorrect" result. As you have it, all ranks are printing suggestions, but it is only filled in rank 0. So the others will all be printing blank entries.
Try some of these changes, especially the last one, and see if that helps.