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Maybe better memory layout

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This commit is contained in:
Alexey Milovidov 2019-12-09 02:55:56 +03:00
parent 171bb14614
commit c738d92411
1 changed files with 7 additions and 7 deletions
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14
dbms/src/Functions/greatCircleDistance.cpp
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@ -44,7 +44,7 @@ float cos_lut[COS_LUT_SIZE + 1]; /// cos(x) table
float asin_sqrt_lut[ASIN_SQRT_LUT_SIZE + 1]; /// asin(sqrt(x)) * earth_diameter table
float sphere_metric_lut[METRIC_LUT_SIZE + 1]; /// sphere metric: the distance for one degree across longitude depending on latitude
float wgs84_metric_lut[METRIC_LUT_SIZE + 1][2]; /// ellipsoid metric: the distance across one degree latitude/longitude depending on latitude
float wgs84_metric_lut[2 * (METRIC_LUT_SIZE + 1)]; /// ellipsoid metric: the distance across one degree latitude/longitude depending on latitude
inline double sqr(double v)
@ -73,8 +73,8 @@ void geodistInit()
/// Squared metric coefficients (for the distance in meters) on a tangent plane, for latitude and longitude (in degrees),
/// depending on the latitude (in radians).
wgs84_metric_lut[i][0] = static_cast<float>(sqr(111132.09 - 566.05 * cos(2 * latitude) + 1.20 * cos(4 * latitude)));
wgs84_metric_lut[i][1] = static_cast<float>(sqr(111415.13 * cos(latitude) - 94.55 * cos(3 * latitude) + 0.12 * cos(5 * latitude)));
wgs84_metric_lut[i * 2] = static_cast<float>(sqr(111132.09 - 566.05 * cos(2 * latitude) + 1.20 * cos(4 * latitude)));
wgs84_metric_lut[i * 2 + 1] = static_cast<float>(sqr(111415.13 * cos(latitude) - 94.55 * cos(3 * latitude) + 0.12 * cos(5 * latitude)));
sphere_metric_lut[i] = static_cast<float>(sqr((EARTH_DIAMETER * PI / 360) * cos(latitude)));
}
@ -163,11 +163,11 @@ float distance(float lon1deg, float lat1deg, float lon2deg, float lat2deg)
}
else if constexpr (method == Method::WGS84)
{
k_lat = wgs84_metric_lut[latitude_midpoint_index][0]
+ (wgs84_metric_lut[latitude_midpoint_index + 1][0] - wgs84_metric_lut[latitude_midpoint_index][0]) * (latitude_midpoint - latitude_midpoint_index);
k_lat = wgs84_metric_lut[latitude_midpoint_index * 2]
+ (wgs84_metric_lut[(latitude_midpoint_index + 1) * 2] - wgs84_metric_lut[latitude_midpoint_index * 2]) * (latitude_midpoint - latitude_midpoint_index);
k_lon = wgs84_metric_lut[latitude_midpoint_index][1]
+ (wgs84_metric_lut[latitude_midpoint_index + 1][1] - wgs84_metric_lut[latitude_midpoint_index][1]) * (latitude_midpoint - latitude_midpoint_index);
k_lon = wgs84_metric_lut[latitude_midpoint_index * 2 + 1]
+ (wgs84_metric_lut[(latitude_midpoint_index + 1) * 2 + 1] - wgs84_metric_lut[latitude_midpoint_index * 2 + 1]) * (latitude_midpoint - latitude_midpoint_index);
}
/// Metric on a tangent plane: it differs from Euclidean metric only by scale of coordinates.