bizarrerie en JAVA

[invitec35bc9ea]

bonjour,
voici une bizarrerie que je viens de rencontrer dans un programme en JAVA:

 Cliquez pour afficher

private void jButton4ActionPerformed(java.a wt.event.ActionEvent evt) {
if(u==1){
if(L3<=L1){
sf=F1;
bm=F1*(L3-L1);
} else{
sf=0;
bm=0;
}
f=-F1*Math.pow(L1,2)*(3*L-L1)/(6*E*igz);
strain=Math.sqrt(Math.abs((fn-t1)*f));
}else
if(u==2){
if(L3<=L1){
sf=(F1/s)*(L-L1-L2);
bm=(F1/s)*(L-L1-L2)*(L3-L1)-(F1/s)*Math.pow((L-L1-L2),2)/2;
}else if(L1<L3 & L3<=(L-L2)){
sf=-(F1/s)*(L3-L1)+(F1/s)*(L-L1-L2);
bm=-(F1/s)*Math.pow((L-L3-L2),2)/2;
}else{
sf=0;
bm=0;
}
f=-F1*Math.pow(L1,2)*(3*L-L1)/(6*E*igz)-F1*Math.pow((L-L2),2)*(2*L+L2)/(6*E*igz)-(F1/s)*Math.pow((L-L1-L2),4)/(8*E*igz);
strain=Math.sqrt(Math.abs((fn-t1)*f));
}else
if(u==3){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L;
}else if(L3<=L){
sf=F1*(L1)/L;
bm=F1*(L-L3)*L1/L;
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(3*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/2));
}else
if(u==4){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L;
}else if(L1<L3 & L3<=(L-L2)){
sf=F2*(L-L2)/L-F1*(L-L1)/L;
bm=(F2*(L-L2)*L2/L-F1*(L-L1)*L1/L)*(L3-L1)/(L-L1-L2)+F1*(L-L1)*L1/L;
}else if(L3<=L){
sf=F2*(L-L2)/L;
bm=F2*(L-L3)*(L-L2)/L;
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(3*E*igz*L)-F2*Math.pow(L2,2)*Math.pow((L-L2),2)/(3*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/2));
}else
if(u==5){
if(L3<=L1){
sf=-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L-L1-L2)*(L-L1+L2)*L3/(2*L);
}else if(L1<L3 & L3<=(L-L2)){
sf=(F1/s)*(L3-L1)-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L3-L1)*(L-L2-L3)/2+(F1/s)*(L-L1-L2)*(L-L1+L2)*L1/(2*L);
}else if(L3<=L){
sf=(F1/s)*(L-L1-L2)*(L+L1-L2)/(2*L);
bm=-(F1/s)*(L-L1-L2)*(L+L1-L2)*(L3-(L+L1-L2)/2)/(2*L)+(F1/s)*(L-L1-L2)*(L+L1-L2)*(L-L1+L2)/(4*L);
}
f=-5*(F1/s)*Math.pow((L-L1-L2),4)/(384*E*igz)-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(3*E*igz*L)-F1*Math.pow(L2,2)*Math.pow((L-L2),2)/(3*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/2));
}else
if(u==6){
if(L3<=(L-L1)){
sf=F1*(L1)/L;
bm=(-F1*L1/L)*L3;
}else if(L3<=L){
sf=-F1;
bm=F1*(L3-L)-F1*L1;
}
f=-F1*Math.pow(L1,2)*(L1+L)/(3*E*igz);
strain=Math.sqrt(Math.abs((fn-t1)*(Math.abs(f)+(F1*L1*Math.p ow(L,2)*Math.sqrt(3)/27*E*igz))));
}else
if(u==7){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L-F1*(L-L1)*L1/(2*L);
}else if(L3<=L){
sf=F1*(L1)/L;
bm=F1*(L-L3)*L1/L+F1*(L-L1)*L1/(2*L);
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(12*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/4));
}else
if(u==8){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L-F1*(L-L1)*L1/(2*L);
}else if(L1<L3 & L3<=(L-L2)){
sf=F2*(L-L2)/L-F1*(L-L1)/L;
bm=(F2*(L2)*(L-L2)/(2*L)-F1*(L-L1)*L1/(2*L))*(L3-L1)/(L-L1-L2)+F1*(L-L1)*L1/(2*L);
}else if(L3<=L){
sf=F2*(L-L2)/L;
bm=F2*(L-L3)*(L-L2)/L+F2*(L2)*(L-L2)/(2*L);
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(12*E*igz*L)-F2*Math.pow(L2,2)*Math.pow((L-L2),2)/(12*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/4));
}else
if(u==9){
if(L3<=L1){
sf=-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L-L1-L2)*(L-L1+L2)*L3/(2*L)-(F1/s)*(L-L1-L2)*(L-L1+L2)*(L+L1-L2)/(4*L);
}else if(L1<L3 & L3<=(L-L2)){
sf=(F1/s)*(L3-L1)-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L3-L1)*(L-L2-L3)/2+(F1/s)*(L-L1-L2)*(L-L1+L2)*L1/(2*L)+(F1/s)*(L-L1-L2)*(L-L1+L2)*(L+L1-L2)/(4*L);
}else if(L3<=L){
sf=(F1/s)*(L-L1-L2)*(L+L1-L2)/(2*L);
bm=-(F1/s)*(L-L1-L2)*(L+L1-L2)*(L3-(L+L1-L2)/2)/(2*L)+(F1/s)*(L-L1-L2)*(L+L1-L2)*(L-L1+L2)/(8*L);
}
f=-(F1/s)*Math.pow((L-L1-L2),4)/(384*E*igz)-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(12*E*igz*L)-F1*Math.pow(L2,2)*Math.pow((L-L2),2)/(12*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/4));
}


switch(jComboBox14.getSelected Index()) {
case 0:
jTextField34.setText(Double.to String(round(sf,3)));
break;
case 1:
jTextField34.setText(Double.to String(round(sf/1000,3)));
break;
}

switch(jComboBox15.getSelected Index()) {
case 0:
jTextField35.setText(Double.to String(round(bm,3)));
break;
case 1:
jTextField35.setText(Double.to String(round(bm/1000,3)));
break;
}
try {
Double.parseDouble(jTextField2 8.getText());
} catch(NumberFormatException e) {
JOptionPane.showMessageDialog( null,"Invalid Entries");
return;
}
switch(jComboBox20.getSelected Index()) {
case 0:
t1=Double.parseDouble(jTextFie ld28.getText());
break;
case 1:
t1=Double.parseDouble(jTextFie ld28.getText())*1000;
break;
}
stres=-bm*(fn-t1)/igz;

jTextField36.setText(Double.to String(round(stres,3)));

switch(jComboBox7.getSelectedI ndex()) {
case 0:
jTextField20.setText(Double.to String(round(strain,3)));
break;
case 1:
jTextField20.setText(Double.to String(round(strain/1000,3)));
break;
}
switch(jComboBox6.getSelectedI ndex()) {
case 0:
jTextField19.setText(Double.to String(round(f,3)));
break;
case 1:
jTextField19.setText(Double.to String(round(f/1000,3)));
break;
}

jTextField1.setText(Double.toS tring(t1));
jTextField18.setText(Double.to String(fn));
jTextField23.setText(Double.to String(fn-t1));
jTextField24.setText(Double.to String((fn-t1)*f));
jTextField25.setText(Double.to String(Math.abs((fn-t1)*f)));
jTextField26.setText(Double.to String(Math.sqrt(Math.abs((fn-t1)*f))));
jTextField27.setText(Double.to String(strain));
}

voici le probleme:
d'une facon generale lorque t1=fn, strain et stress sont nuls.
selon l'indice "u", la valeur de strain varie mais devrait tjrs etre nulle lorsque t1=fn
j'execute mon programme et j'essaie les valeurs t1=(0,6,12). pour stress c'est bon: nulle en 6, mini en 0 et maxi en 12.
pour strain c'est une autre histoire, je trouve une valeurs pout t1=6, je decide de verifier mes formules avec un crayon et un papier. ils ont l'air correctes.
j'ai donc ajouté des textfiels pour essayer l'equation de strain element par element.
c'est là que ça devient bizarre:
Double.toString(Math.sqrt(Math .abs((fn-t1)*f))) me donne bien "0" pour t1=6 alors que Double.toString(strain) me donne 4.67. et si vous regardez l'expression de strain pour u=1 c'est bien:

strain=Math.sqrt(Math.abs((fn-t1)*f));

et pour tous les autres u c'est de la meme forme avec un coef 1/2 ou 1/4 en plus.
qqun pourrait-il m'expliquer d'ou vient ce truc, svp?
merci
-----

[invitec35bc9ea]

si besoin,
voici le code en entier:

[invitebda71f50]

une piste rapide: strain est bien un double ? (flottant double - 8 octets).

[invitec35bc9ea]

oui. c'est bien un double

[A voir en vidéo sur Futura]

[invitec35bc9ea]

bonsoir,
j'ai resolu le probleme:
j'ai remarqué, par hazard, que quand j'appuiais une deuxieme fois sur le jButton, j'avais le bon resultat. j'ai donc edité strain=...; pour lui affecter fn, fn-t1, etc et j'ai pu remarqué que le probleme apparaissait quand j'ajoutais t1. en fait j'avais la lecture de t1 positionnée apres strain= alors à chaque fois il prenait la valeur precedente de t1 et comme t1 etait innitialisé à 0, c'est pour cette valeur qu'etait calculé strain. j'ai donc changé la position de la lecture de t1 et ça s'est arrangé:

 Cliquez pour afficher

private void jButton4ActionPerformed(java.a wt.event.ActionEvent evt) {
if(jTextField13.isEnabled()){
try {
Double.parseDouble(jTextField1 3.getText());
} catch(NumberFormatException e) {
JOptionPane.showMessageDialog( null,"Invalid Entries");
return;
}
switch(jComboBox1.getSelectedI ndex()) {
case 0:
F1=Double.parseDouble(jTextFie ld13.getText());
break;
case 1:
F1=Double.parseDouble(jTextFie ld13.getText())*1000;
break;
}
}
if(jTextField14.isEnabled()){
try {
Double.parseDouble(jTextField1 4.getText());
} catch(NumberFormatException e) {
JOptionPane.showMessageDialog( null,"Invalid Entries");
return;
}
switch(jComboBox2.getSelectedI ndex()) {
case 0:
F2=Double.parseDouble(jTextFie ld14.getText());
break;
case 1:
F2=Double.parseDouble(jTextFie ld14.getText())*1000;
break;
}
}
if(jTextField39.isEnabled()){
try {
Double.parseDouble(jTextField3 9.getText());
} catch(NumberFormatException e) {
JOptionPane.showMessageDialog( null,"Invalid Entries");
return;
}
switch(jComboBox16.getSelected Index()) {
case 0:
s=Double.parseDouble(jTextFiel d39.getText());
break;
case 1:
s=Double.parseDouble(jTextFiel d39.getText())*1000;
break;
}
}

try {
Double.parseDouble(jTextField2 9.getText());
} catch(NumberFormatException e) {
JOptionPane.showMessageDialog( null,"Invalid Entries");
return;
}
switch(jComboBox18.getSelected Index()) {
case 0:
L3=Double.parseDouble(jTextFie ld29.getText());
break;
case 1:
L3=Double.parseDouble(jTextFie ld29.getText())*1000;
break;
}


try {
Double.parseDouble(jTextField2 8.getText());
} catch(NumberFormatException e) {
JOptionPane.showMessageDialog( null,"Invalid Entries");
return;
}
switch(jComboBox20.getSelected Index()) {
case 0:
t1=Double.parseDouble(jTextFie ld28.getText());
break;
case 1:
t1=Double.parseDouble(jTextFie ld28.getText())*1000;
break;
}

if(u==1){
if(L3<=L1){
sf=F1;
bm=F1*(L3-L1);
} else{
sf=0;
bm=0;
}
f=-F1*Math.pow(L1,2)*(3*L-L1)/(6*E*igz);
strain=Math.sqrt(Math.abs((fn-t1)*f));
}else
if(u==2){
if(L3<=L1){
sf=(F1/s)*(L-L1-L2);
bm=(F1/s)*(L-L1-L2)*(L3-L1)-(F1/s)*Math.pow((L-L1-L2),2)/2;
}else if(L1<L3 & L3<=(L-L2)){
sf=-(F1/s)*(L3-L1)+(F1/s)*(L-L1-L2);
bm=-(F1/s)*Math.pow((L-L3-L2),2)/2;
}else{
sf=0;
bm=0;
}
f=-F1*Math.pow(L1,2)*(3*L-L1)/(6*E*igz)-F1*Math.pow((L-L2),2)*(2*L+L2)/(6*E*igz)-(F1/s)*Math.pow((L-L1-L2),4)/(8*E*igz);
strain=Math.sqrt(Math.abs((fn-t1)*f));
}else
if(u==3){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L;
}else if(L3<=L){
sf=F1*(L1)/L;
bm=F1*(L-L3)*L1/L;
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(3*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/2));
}else
if(u==4){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L;
}else if(L1<L3 & L3<=(L-L2)){
sf=F2*(L-L2)/L-F1*(L-L1)/L;
bm=(F2*(L-L2)*L2/L-F1*(L-L1)*L1/L)*(L3-L1)/(L-L1-L2)+F1*(L-L1)*L1/L;
}else if(L3<=L){
sf=F2*(L-L2)/L;
bm=F2*(L-L3)*(L-L2)/L;
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(3*E*igz*L)-F2*Math.pow(L2,2)*Math.pow((L-L2),2)/(3*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/2));
}else
if(u==5){
if(L3<=L1){
sf=-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L-L1-L2)*(L-L1+L2)*L3/(2*L);
}else if(L1<L3 & L3<=(L-L2)){
sf=(F1/s)*(L3-L1)-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L3-L1)*(L-L2-L3)/2+(F1/s)*(L-L1-L2)*(L-L1+L2)*L1/(2*L);
}else if(L3<=L){
sf=(F1/s)*(L-L1-L2)*(L+L1-L2)/(2*L);
bm=-(F1/s)*(L-L1-L2)*(L+L1-L2)*(L3-(L+L1-L2)/2)/(2*L)+(F1/s)*(L-L1-L2)*(L+L1-L2)*(L-L1+L2)/(4*L);
}
f=-5*(F1/s)*Math.pow((L-L1-L2),4)/(384*E*igz)-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(3*E*igz*L)-F1*Math.pow(L2,2)*Math.pow((L-L2),2)/(3*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/2));
}else
if(u==6){
if(L3<=(L-L1)){
sf=F1*(L1)/L;
bm=(-F1*L1/L)*L3;
}else if(L3<=L){
sf=-F1;
bm=F1*(L3-L)-F1*L1;
}
f=-F1*Math.pow(L1,2)*(L1+L)/(3*E*igz);
strain=Math.sqrt(Math.abs((fn-t1)*(Math.abs(f)+(F1*L1*Math.p ow(L,2)*Math.sqrt(3)/27*E*igz))));
}else
if(u==7){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L-F1*(L-L1)*L1/(2*L);
}else if(L3<=L){
sf=F1*(L1)/L;
bm=F1*(L-L3)*L1/L+F1*(L-L1)*L1/(2*L);
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(12*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/4));
}else
if(u==8){
if(L3<=L1){
sf=-F1*(L-L1)/L;
bm=F1*(L-L1)*L3/L-F1*(L-L1)*L1/(2*L);
}else if(L1<L3 & L3<=(L-L2)){
sf=F2*(L-L2)/L-F1*(L-L1)/L;
bm=(F2*(L2)*(L-L2)/(2*L)-F1*(L-L1)*L1/(2*L))*(L3-L1)/(L-L1-L2)+F1*(L-L1)*L1/(2*L);
}else if(L3<=L){
sf=F2*(L-L2)/L;
bm=F2*(L-L3)*(L-L2)/L+F2*(L2)*(L-L2)/(2*L);
}
f=-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(12*E*igz*L)-F2*Math.pow(L2,2)*Math.pow((L-L2),2)/(12*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/4));
}else
if(u==9){
if(L3<=L1){
sf=-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L-L1-L2)*(L-L1+L2)*L3/(2*L)-(F1/s)*(L-L1-L2)*(L-L1+L2)*(L+L1-L2)/(4*L);
}else if(L1<L3 & L3<=(L-L2)){
sf=(F1/s)*(L3-L1)-(F1/s)*(L-L1-L2)*(L-L1+L2)/(2*L);
bm=(F1/s)*(L3-L1)*(L-L2-L3)/2+(F1/s)*(L-L1-L2)*(L-L1+L2)*L1/(2*L)+(F1/s)*(L-L1-L2)*(L-L1+L2)*(L+L1-L2)/(4*L);
}else if(L3<=L){
sf=(F1/s)*(L-L1-L2)*(L+L1-L2)/(2*L);
bm=-(F1/s)*(L-L1-L2)*(L+L1-L2)*(L3-(L+L1-L2)/2)/(2*L)+(F1/s)*(L-L1-L2)*(L+L1-L2)*(L-L1+L2)/(8*L);
}
f=-(F1/s)*Math.pow((L-L1-L2),4)/(384*E*igz)-F1*Math.pow(L1,2)*Math.pow((L-L1),2)/(12*E*igz*L)-F1*Math.pow(L2,2)*Math.pow((L-L2),2)/(12*E*igz*L);
strain=Math.sqrt(Math.abs((fn-t1)*f/4));
}

stres=-bm*(fn-t1)/igz;

switch(jComboBox14.getSelected Index()) {
case 0:
jTextField34.setText(Double.to String(round(sf,3)));
break;
case 1:
jTextField34.setText(Double.to String(round(sf/1000,3)));
break;
}

switch(jComboBox15.getSelected Index()) {
case 0:
jTextField35.setText(Double.to String(round(bm,3)));
break;
case 1:
jTextField35.setText(Double.to String(round(bm/1000,3)));
break;
}

jTextField36.setText(Double.to String(round(stres,3)));

switch(jComboBox7.getSelectedI ndex()) {
case 0:
jTextField20.setText(Double.to String(round(strain,3)));
break;
case 1:
jTextField20.setText(Double.to String(round(strain/1000,3)));
break;
}
switch(jComboBox6.getSelectedI ndex()) {
case 0:
jTextField19.setText(Double.to String(round(f,3)));
break;
case 1:
jTextField19.setText(Double.to String(round(f/1000,3)));
break;
}
}

merci