lbfgsbrs 0.1.1

Rust port of L-BFGS-B-C
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223

/// Performs the operation y = αx + y where:
/// * n: number of elements to process
/// * da (α): scalar multiplier
/// * dx (x): input vector
/// * incx: stride for vector x
/// * dy (y): input/output vector
/// * incy: stride for vector y
/// 
/// Returns:
///  * 0 on success
///  * -1 if input slices are too small
pub fn daxpy(n: i32, da: f64, dx: &[f64], incx: i32, dy: &mut [f64], incy: i32) -> i32 {
    if n <= 0 {
        return 0;
    }
    if da == 0.0 {
        return 0;
    }

    // Validate slice lengths
    let dx_required = (1 + (n - 1) * incx.abs()) as usize;
    let dy_required = (1 + (n - 1) * incy.abs()) as usize;
    
    if dx.len() < dx_required || dy.len() < dy_required {
        return -1; // Error: slices too small
    }

    if incx == 1 && incy == 1 {
        let m = n % 4;
        if m != 0 {
            for i in 0..m {
                dy[i as usize] += da * dx[i as usize];
            }
            if n < 4 {
                return 0;
            }
        }
        
        let mp1 = m;
        for i in (mp1..n).step_by(4) {
            dy[i as usize] += da * dx[i as usize];
            dy[(i + 1) as usize] += da * dx[(i + 1) as usize];
            dy[(i + 2) as usize] += da * dx[(i + 2) as usize];
            dy[(i + 3) as usize] += da * dx[(i + 3) as usize];
        }
    } else {
        let mut ix = if incx < 0 { (-n + 1) * incx } else { 0 };
        let mut iy = if incy < 0 { (-n + 1) * incy } else { 0 };
        
        for _ in 0..n {
            dy[iy as usize] += da * dx[ix as usize];
            ix += incx;
            iy += incy;
        }
    }
    0
}

/// Copies vector x into vector y where:
/// * n: number of elements to copy
/// * dx (x): source vector
/// * incx: stride for vector x
/// * dy (y): destination vector
/// * incy: stride for vector y
/// 
/// Returns:
///  * 0 on success
///  * -1 if input slices are too small
pub fn dcopy(n: i32, dx: &[f64], incx: i32, dy: &mut [f64], incy: i32) -> i32 {
    if n <= 0 {
        return 0;
    }

    // Validate slice lengths
    let dx_required = (1 + (n - 1) * incx.abs()) as usize;
    let dy_required = (1 + (n - 1) * incy.abs()) as usize;
    
    if dx.len() < dx_required || dy.len() < dy_required {
        return -1; // Error: slices too small
    }

    if incx == 1 && incy == 1 {
        let m = n % 7;
        if m != 0 {
            for i in 0..m {
                dy[i as usize] = dx[i as usize];
            }
            if n < 7 {
                return 0;
            }
        }
        
        let mp1 = m;
        for i in (mp1..n).step_by(7) {
            dy[i as usize] = dx[i as usize];
            dy[(i + 1) as usize] = dx[(i + 1) as usize];
            dy[(i + 2) as usize] = dx[(i + 2) as usize];
            dy[(i + 3) as usize] = dx[(i + 3) as usize];
            dy[(i + 4) as usize] = dx[(i + 4) as usize];
            dy[(i + 5) as usize] = dx[(i + 5) as usize];
            dy[(i + 6) as usize] = dx[(i + 6) as usize];
        }
    } else {
        let mut ix = if incx < 0 { (-n + 1) * incx } else { 0 };
        let mut iy = if incy < 0 { (-n + 1) * incy } else { 0 };
        
        for _ in 0..n {
            dy[iy as usize] = dx[ix as usize];
            ix += incx;
            iy += incy;
        }
    }
    0
}

/// Computes the dot product of two vectors where:
/// * n: number of elements to process
/// * dx (x): first input vector
/// * incx: stride for vector x
/// * dy (y): second input vector
/// * incy: stride for vector y
/// 
/// Returns:
///  * The dot product result
///  * 0.0 if input slices are too small or n <= 0
pub fn ddot(n: i32, dx: &[f64], incx: i32, dy: &[f64], incy: i32) -> f64 {
    if n <= 0 {
        return 0.0;
    }

    // Validate slice lengths
    let dx_required = (1 + (n - 1) * incx.abs()) as usize;
    let dy_required = (1 + (n - 1) * incy.abs()) as usize;
    
    if dx.len() < dx_required || dy.len() < dy_required {
        return 0.0; // Error case
    }

    let mut dtemp = 0.0;
    
    if incx == 1 && incy == 1 {
        let m = n % 5;
        if m != 0 {
            for i in 0..m {
                dtemp += dx[i as usize] * dy[i as usize];
            }
            if n < 5 {
                return dtemp;
            }
        }
        
        let mp1 = m;
        for i in (mp1..n).step_by(5) {
            dtemp += dx[i as usize] * dy[i as usize]
                + dx[(i + 1) as usize] * dy[(i + 1) as usize]
                + dx[(i + 2) as usize] * dy[(i + 2) as usize]
                + dx[(i + 3) as usize] * dy[(i + 3) as usize]
                + dx[(i + 4) as usize] * dy[(i + 4) as usize];
        }
    } else {
        let mut ix = if incx < 0 { (-n + 1) * incx } else { 0 };
        let mut iy = if incy < 0 { (-n + 1) * incy } else { 0 };
        
        for _ in 0..n {
            dtemp += dx[ix as usize] * dy[iy as usize];
            ix += incx;
            iy += incy;
        }
    }
    dtemp
}

/// Scales a vector by a constant where:
/// * n: number of elements to process
/// * da (α): scalar multiplier
/// * dx (x): input/output vector
/// * incx: stride for vector x
/// 
/// Returns:
///  * 0 on success
///  * -1 if input slice is too small
pub fn dscal(n: i32, da: f64, dx: &mut [f64], incx: i32) -> i32 {
    if n <= 0 || incx <= 0 {
        return 0;
    }

    // Validate slice length
    let dx_required = (1 + (n - 1) * incx.abs()) as usize;
    
    if dx.len() < dx_required {
        return -1; // Error: slice too small
    }

    if incx == 1 {
        let m = n % 5;
        if m != 0 {
            for i in 0..m {
                dx[i as usize] = da * dx[i as usize];
            }
            if n < 5 {
                return 0;
            }
        }
        
        let mp1 = m;
        for i in (mp1..n).step_by(5) {
            dx[i as usize] = da * dx[i as usize];
            dx[(i + 1) as usize] = da * dx[(i + 1) as usize];
            dx[(i + 2) as usize] = da * dx[(i + 2) as usize];
            dx[(i + 3) as usize] = da * dx[(i + 3) as usize];
            dx[(i + 4) as usize] = da * dx[(i + 4) as usize];
        }
    } else {
        let mut ix = if incx < 0 { (-n + 1) * incx } else { 0 };
        
        for _ in 0..n {
            dx[ix as usize] = da * dx[ix as usize];
            ix += incx;
        }
    }
    0
}