136 {
137 double neighbors[] = new double[40];
138 double neighborsStrict[] = new double[40];
139 double z = Double.NaN;
140
141 // Test inputs greater than 1.0.
142 neighbors[0] = Math.log10(1.0);
143 neighborsStrict[0] = StrictMath.log10(1.0);
144
145 double input[] = new double[40];
146 int half = input.length/2;
147
148
149 // Initialize input to the 40 consecutive double values
150 // "centered" at 1.0.
151 double up = Double.NaN;
152 double down = Double.NaN;
153 for(int i = 0; i < half; i++) {
154 if (i == 0) {
155 input[half] = 1.0;
156 up = FpUtils.nextUp(1.0);
157 down = FpUtils.nextDown(1.0);
158 } else {
159 input[half + i] = up;
160 input[half - i] = down;
161 up = FpUtils.nextUp(up);
162 down = FpUtils.nextDown(down);
163 }
164 }
165 input[0] = FpUtils.nextDown(input[1]);
166
167 for(int i = 0; i < neighbors.length; i++) {
168 neighbors[i] = Math.log10(input[i]);
169 neighborsStrict[i] = StrictMath.log10(input[i]);
170
171 // Test accuracy.
172 z = input[i] - 1.0;
173 double expected = (z - (z*z)*0.5)/LN_10;
174 if ( Math.abs(neighbors[i] - expected ) > 3*Math.ulp(expected) ) {
175 failures++;
176 System.err.println("For input near 1.0 " + input[i] +
177 ", Math.log10(1+z) was more than 3 ulps different from " +
178 "(z-(z^2)/2)/ln(10): log10(input) = " + neighbors[i] +
179 "\texpected about = " + expected);
180 }
181
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136 {
137 double neighbors[] = new double[40];
138 double neighborsStrict[] = new double[40];
139 double z = Double.NaN;
140
141 // Test inputs greater than 1.0.
142 neighbors[0] = Math.log10(1.0);
143 neighborsStrict[0] = StrictMath.log10(1.0);
144
145 double input[] = new double[40];
146 int half = input.length/2;
147
148
149 // Initialize input to the 40 consecutive double values
150 // "centered" at 1.0.
151 double up = Double.NaN;
152 double down = Double.NaN;
153 for(int i = 0; i < half; i++) {
154 if (i == 0) {
155 input[half] = 1.0;
156 up = Math.nextUp(1.0);
157 down = FpUtils.nextDown(1.0);
158 } else {
159 input[half + i] = up;
160 input[half - i] = down;
161 up = Math.nextUp(up);
162 down = FpUtils.nextDown(down);
163 }
164 }
165 input[0] = FpUtils.nextDown(input[1]);
166
167 for(int i = 0; i < neighbors.length; i++) {
168 neighbors[i] = Math.log10(input[i]);
169 neighborsStrict[i] = StrictMath.log10(input[i]);
170
171 // Test accuracy.
172 z = input[i] - 1.0;
173 double expected = (z - (z*z)*0.5)/LN_10;
174 if ( Math.abs(neighbors[i] - expected ) > 3*Math.ulp(expected) ) {
175 failures++;
176 System.err.println("For input near 1.0 " + input[i] +
177 ", Math.log10(1+z) was more than 3 ulps different from " +
178 "(z-(z^2)/2)/ln(10): log10(input) = " + neighbors[i] +
179 "\texpected about = " + expected);
180 }
181
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