Value and type of last evaluated expression: Address of array element: Address of array elementx: (none)
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Code
Header...
/*
* Demonstrate the use of successive halving to solve
* atan(x) + exp(x) + fabs(log(x) = y
*/
int main(){
» double y, ytarget=11.789474563, x, xmin=0, xmax=ytarget;
»printf("Diag: target is %g\n", ytarget);
» do{
»x=(xmin+xmax)/2.0;
»y=atan(x)+exp(x)+fabs(log(x));
»printf("Diag: xmin = %g, xmax = %g, y = %g\n", xmin, xmax, y);
» if (y<ytarget)
xmin=x;
else
xmax=x;
}while (fabs(y-ytarget)>1e-6) ;
»printf("The solution is %g\n", x);
» return 0;
} ...
Memory
main()
128
129
130
131
132
133
134
135
y = 6.4027592e-139
136
137
138
139
140
141
142
143
ytarget = 11.7894746
144
145
146
147
148
149
150
151
x = -2.25362837e+136
152
153
154
155
156
157
158
159
xmin = 0
160
161
162
163
164
165
166
167
xmax = 11.7894746
NB: the actual memory address of each variable is
the address shown plus 4294737056 (0xFFFC7CA0).
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.
Show output
(Before looking at the output,
work out what you think it put should be and see if you are right.)
Output
Diag: target is 11.7895
Diag: xmin = 0, xmax = 11.7895, y = 366.298
Diag: xmin = 0, xmax = 5.89474, y = 21.3804
Diag: xmin = 0, xmax = 2.94737, y = 5.72765
Diag: xmin = 1.47368, xmax = 2.94737, y = 11.0597
Diag: xmin = 2.21053, xmax = 2.94737, y = 15.3315
Diag: xmin = 2.21053, xmax = 2.57895, y = 13.0138
Diag: xmin = 2.21053, xmax = 2.39474, y = 11.9956
Diag: xmin = 2.21053, xmax = 2.30263, y = 11.5179
Diag: xmin = 2.25658, xmax = 2.30263, y = 11.7542
Diag: xmin = 2.27961, xmax = 2.30263, y = 11.8743
Diag: xmin = 2.27961, xmax = 2.29112, y = 11.8141
Diag: xmin = 2.27961, xmax = 2.28536, y = 11.7841
Diag: xmin = 2.28248, xmax = 2.28536, y = 11.7991
Diag: xmin = 2.28248, xmax = 2.28392, y = 11.7916
Diag: xmin = 2.28248, xmax = 2.2832, y = 11.7879
Diag: xmin = 2.28284, xmax = 2.2832, y = 11.7897
Diag: xmin = 2.28284, xmax = 2.28302, y = 11.7888
Diag: xmin = 2.28293, xmax = 2.28302, y = 11.7893
Diag: xmin = 2.28298, xmax = 2.28302, y = 11.7895
Diag: xmin = 2.28298, xmax = 2.283, y = 11.7894
Diag: xmin = 2.28299, xmax = 2.283, y = 11.7894
Diag: xmin = 2.283, xmax = 2.283, y = 11.7895
The solution is 2.283
