I implemented a calculator in my app using the method below but it seems to be coming up with errors
- (IBAction)calculate {
float x = ([textField1.text floatValue]);
if (x>=)
{
(x<=14000,x*0.0125);
(x<=30000,175+x-14000*0.015);
(x<=80000,415+x-30000*0.0175);
(x<=300000.1290+x-80000*0.035);
(x<=1000000,8990+x-300000*0.045);
(x<=3000000,40490+x-1000000*0.055);
}
}
I'm guessing here (because what you posted isn't C/C++/ObjC syntax):
- (IBAction)calculate {
float x = ([textField1.text floatValue]);
if (x <= 14000) {
x *= 0.0125;
} else if (x < 30000) {
x = ((x - 14000) * 0.015) + 175;
} else if (x < 80000) {
x = ((x - 30000) * 0.0175) + 415;
} else if (x < 300000) {
x = ((x - 80000) * 0.035) + 1290;
} else if (x < 1000000) {
x = ((x - 300000) * 0.045) + 8990;
} else if (x < 3000000) {
x = ((x - 1000000) * 0.055) + 40490;
}
}
Related
I'm implementing in code an algorithm for computing inverse polynomials in the NTRU cryptosystem, and I'm using the paper "Almost Inverses and Fast NTRU Key Creation" by Joseph H. Silverman. I implemented the second pseudo-code as:
int inverse_mod_p(polynomial *r, polynomial *a)
{
int k;
int16_t b[NTRU_N + 1], c[NTRU_N + 1], f[NTRU_N + 1], g[NTRU_N + 1];
int i;
int16_t aux;
int zero_f;
int constant_f;
int deg_fg;
memset(b, 0, (NTRU_N + 1) * sizeof(int16_t));
b[0] = 1;
memset(c, 0, (NTRU_N + 1) * sizeof(int16_t));
memcpy(f, a->coeffs, NTRU_N * sizeof(int16_t));
f[NTRU_N] = 0;
memset(g, 0, (NTRU_N + 1) * sizeof(int16_t));
g[0] = -1;
g[NTRU_N] = 1;
while (1)
{
zero_f = 1;
for (i = 0; i < NTRU_N + 1; i++)
{
if (f[i] != 0)
{
zero_f = 0;
break;
}
}
if (zero_f)
return 1;
while (f[0] == 0)
{
for (i = 0; i < NTRU_N; i++)
{
f[i] = f[i + 1];
c[NTRU_N - i] = c[NTRU_N - i - 1];
}
f[NTRU_N] = 0;
c[0] = 0;
k++;
}
constant_f = 1;
for (i = 1; i < NTRU_N + 1; i++)
{
if (f[i] != 0)
{
constant_f = 0;
break;
}
}
if (constant_f)
break;
deg_fg = 0;
for (i = NTRU_N; i >= 0; i--)
{
if (f[i] == 0 && g[i] != 0)
{
deg_fg = 1;
break;
}
else if (f[i] != 0 && g[i] == 0)
{
break;
}
}
if (deg_fg)
{
for (i = 0; i < NTRU_N + 1; i++)
{
aux = f[i];
f[i] = g[i];
g[i] = aux;
aux = b[i];
b[i] = c[i];
c[i] = aux;
}
}
if (f[0] == g[0])
{
for (i = 0; i < NTRU_N + 1; i++)
{
f[i] = (f[i] - g[i] + 3) % 3;
b[i] = (b[i] - c[i] + 3) % 3;
}
}
else
{
for (i = 0; i < NTRU_N + 1; i++)
{
f[i] = (f[i] + g[i] + 3) % 3;
b[i] = (b[i] + c[i] + 3) % 3;
}
}
}
k = k % NTRU_N;
for (i = NTRU_N - 1; i >= 0; i--)
{
if (i - k < 0)
r->coeffs[i - k + NTRU_N] = b[i] * f[0];
else
r->coeffs[i - k] = b[i] * f[0];
}
for (i = 0; i < NTRU_N; i++)
r->coeffs[i] = (r->coeffs[i] + 3) % 3;
return 0;
}
But this seems to be wrong. I tested it using the example giveng in Wikipedia: https://en.wikipedia.org/wiki/NTRUEncrypt . The polynomial -1 + x + x^2 - x^4 + x^6 + x^9 - x^10 should have as inverse the polynomial 1 + 2x + 2x^3 + 2x^4 + x^5 + 2x^7 + x^8 - x^10 , but I got the following result:
Polinomial:
-1 1 1 0 -1 0 1 0 0 1 -1
Inverse polinomial:
0 2 2 1 0 2 1 2 0 1 2
Where is the error in the implementation?
I am working on image seam carving project, looking for some help. Can someone tell me what am I doing wrong here, Hyperskill is not accepting my solution. I am pretty sure I did not understand the project statement correctly. (I’ve been fighting it for a week)
Project: https://hyperskill.org/projects/100/stages/553/implement
First I am finding the minimum seam from all possible seams.
var minX = 0
// (minSeamX, 0) would be the coordinate of the minimum seam
var minSeamX = 0
var minSeam = Double.MAX_VALUE
//Starting from top left find the sum of pixel energies for all possible seams(#width number of possible seams)
for (column in 0 until width) {
var totalSeam = 0.0
var xHigh = column
var xLow = column
var min = Double.MAX_VALUE
for (y in 0 until height) {
for (x in xLow..xHigh) {
if (x < 0 || x > width - 1) continue
val energy = calculateEnergy(x, y, bufferedImage)
// println("Energy $x $y $energy")
if (energy < min) {
min = energy
minX = x
}
}
totalSeam += min
min = Double.MAX_VALUE
xLow = minX - 1
xHigh = minX + 1
}
if (totalSeam < minSeam) {
minSeamX = column
minSeam = totalSeam
}
println("total:$totalSeam")
}
after that I am applying the color to the minimum seam pixels
var xLow = minSeamX
var xHigh = minSeamX
var min = Double.MAX_VALUE
for (y in 0 until height) {
for (x in xLow..xHigh) {
val energy = calculateEnergy(x, y, bufferedImage)
if (energy < min) {
min = energy
minX = x
}
}
val createGraphics = applyColor(outImage, minX, y)
min = Double.MAX_VALUE
xLow = minX - 1
xHigh = minX + 1
}
Complete code
package seamcarving
import java.awt.Color
import java.awt.Graphics2D
import java.awt.image.BufferedImage
import java.io.File
import javax.imageio.ImageIO
import kotlin.math.pow
import kotlin.math.sqrt
fun main(args: Array<String>) {
val bufferedImage = ImageIO.read(File("/Users/name/Downloads/images/blue.png"))
val outImage = ImageIO.read(File("/Users/name/Downloads/images/blue.png"))
val height = bufferedImage.height
val width = bufferedImage.width
var minX = 0
// (minSeamX, 0) would be the coordinate of the minimum seam
var minSeamX = 0
var minSeam = Double.MAX_VALUE
//Starting from top left find the sum of pixel energies for all possible seams(#width number of possible seams)
for (column in 0 until width) {
var totalSeam = 0.0
var xHigh = column
var xLow = column
var min = Double.MAX_VALUE
for (y in 0 until height) {
for (x in xLow..xHigh) {
if (x < 0 || x > width - 1) continue
val energy = calculateEnergy(x, y, bufferedImage)
// println("Energy $x $y $energy")
if (energy < min) {
min = energy
minX = x
}
}
totalSeam += min
min = Double.MAX_VALUE
xLow = minX - 1
xHigh = minX + 1
}
if (totalSeam < minSeam) {
minSeamX = column
minSeam = totalSeam
}
println("total:$totalSeam")
}
var xLow = minSeamX
var xHigh = minSeamX
var min = Double.MAX_VALUE
for (y in 0 until height) {
for (x in xLow..xHigh) {
val energy = calculateEnergy(x, y, bufferedImage)
if (energy < min) {
min = energy
minX = x
}
}
val createGraphics = applyColor(outImage, minX, y)
min = Double.MAX_VALUE
xLow = minX - 1
xHigh = minX + 1
}
// for (x in 0 until width) {
// for (y in 0 until height) {
// val intensity = ((255.0 * array[x][y]) / max).toInt()
// val color = Color(intensity, intensity, intensity)
//// outputImage.setRGB(x, y, intensity)
// createGraphics.paint = color
// createGraphics.fillRect(x, y, 1, 1)
// }
// }
ImageIO.write(outImage, "png", File("out.png"))
// ImageIO.write(bufferedImage, "png", File("${args[3]}"))
}
private fun applyColor(outputImage: BufferedImage, maxX: Int, maxY: Int): Graphics2D? {
val createGraphics = outputImage.createGraphics()
val color = Color(255, 0, 0)
createGraphics.paint = color
createGraphics.fillRect(maxX, maxY, 1, 1)
return createGraphics
}
private fun calculateEnergy(x: Int, y: Int, bufferedImage: BufferedImage): Double {
return sqrt(getXGradient(x, y, bufferedImage) + getYGradient(x, y, bufferedImage))
}
fun getXGradient(x: Int, y: Int, inImage: BufferedImage): Double {
val width = inImage.width
var xx = x
var yy = y
if (x == 0) xx = 1
if (x == width - 1) xx = x - 1
val lc = Color(inImage.getRGB(xx - 1, yy))
val rc = Color(inImage.getRGB(xx + 1, yy))
return (lc.red - rc.red).toDouble().pow(2.0) + (lc.green - rc.green).toDouble().pow(2.0) + (lc.blue - rc.blue).toDouble().pow(2.0)
}
fun getYGradient(x: Int, y: Int, inImage: BufferedImage): Double {
val height = inImage.height
var xx = x
var yy = y
if (y == 0) yy = 1
if (y == height - 1) yy = y - 1
val lc = Color(inImage.getRGB(xx, yy - 1))
val rc = Color(inImage.getRGB(xx, yy + 1))
return (lc.red - rc.red).toDouble().pow(2.0) + (lc.green - rc.green).toDouble().pow(2.0) + (lc.blue - rc.blue).toDouble().pow(2.0)
}
How do you use the waveshapernode in the web audio api? particular the curve Float32Array attribute?
Feel free to look at an example here.
In detail, I create a waveshaper curve with this function:
WAAMorningStar.prototype.createWSCurve = function (amount, n_samples) {
if ((amount >= 0) && (amount < 1)) {
ND.dist = amount;
var k = 2 * ND.dist / (1 - ND.dist);
for (var i = 0; i < n_samples; i+=1) {
// LINEAR INTERPOLATION: x := (c - a) * (z - y) / (b - a) + y
// a = 0, b = 2048, z = 1, y = -1, c = i
var x = (i - 0) * (1 - (-1)) / (n_samples - 0) + (-1);
this.wsCurve[i] = (1 + k) * x / (1+ k * Math.abs(x));
}
}
Then "load" it in a waveshaper node like this:
this.createWSCurve(ND.dist, this.nSamples);
this.sigmaDistortNode = this.context.createWaveShaper();
this.sigmaDistortNode.curve = this.wsCurve;
Everytime I need to change the distortion parameter, I re-create the waveshaper curve:
WAAMorningStar.prototype.setDistortion = function (distValue) {
var distCorrect = distValue;
if (distValue < -1) {
distCorrect = -1;
}
if (distValue >= 1) {
distCorrect = 0.985;
}
this.createWSCurve (distCorrect, this.nSamples);
}
(I use distCorrect to make the distortion sound nicer, values found euristically).
You can find the algorithm I use to create the waveshaper curve here
I would like to perform the division of num by 60 which is not power of two using right shift operation. How do I do this?
If I want num/64, I can do num >> 6 since 64 = 2^6
How do I do it for 60?
This should work:
public static final long divisionUsingShift(int x, int y) {
int a, b, q, counter;
q = 0;
if (y != 0) {
while (x >= y) {
a = x >> 1;
b = y;
counter = 1;
while (a >= b) {
b <<= 1;
counter <<= 1;
}
x -= b;
q += counter;
}
}
return q;
}
I'm looking for an objective-c library or just the functions that can handle calculating the Wilson Score Interval explained here:
http://www.evanmiller.org/how-not-to-sort-by-average-rating.html
For reference, here's a Ruby implementation from the same source:
require 'statistics2'
def ci_lower_bound(pos, n, power)
if n == 0
return 0
end
z = Statistics2.pnormaldist(1-power/2)
phat = 1.0*pos/n
(phat + z*z/(2*n) - z * Math.sqrt((phat*(1-phat)+z*z/(4*n))/n))/(1+z*z/n)
end
Assuming the implementation for pnormaldist listed here is correct (i've copied it verbatim):
double pnormaldist(double qn)
{
double b[] = {1.570796288, 0.03706987906, -0.8364353589e-3, -0.2250947176e-3, 0.6841218299e-5, 0.5824238515e-5, -0.104527497e-5, 0.8360937017e-7, -0.3231081277e-8, 0.3657763036e-10, 0.6936233982e-12};
if(qn < 0.0 || 1.0 < qn)
return 0.0;
if(qn == 0.5)
return 0.0;
double w1 = qn;
if(qn > 0.5)
w1 = 1.0 - w1;
double w3 = -log(4.0 * w1 * (1.0 - w1));
w1 = b[0];
int i=1;
for(;i<11;i++)
w1 += b[i] * pow(w3,i);
if(qn > 0.5)
return sqrt(w1*w3);
return -sqrt(w1*w3);
}
double ci_lower_bound(int pos, int n, double power)
{
if(n==0)
return 0.0;
double z = pnormaldist(1-power/2);
double phat = 1.0*pos/n;
return (phat + z*z/(2*n) - z * sqrt((phat*(1-phat)+z*z/(4*n))/n))/(1+z*z/n);
}