Mercurial > gemma

annotate pkg/common/linear.go @ 5591:0011f50cf216 surveysperbottleneckid

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Removed no longer used alternative api for surveys/ endpoint. As bottlenecks in the summary for SR imports are now identified by their id and no longer by the (not guarantied to be unique!) name, there is no longer the need to request survey data by the name+date tuple (which isn't reliable anyway). So the workaround was now reversed.
author Sascha Wilde <wilde@sha-bang.de>
date Wed, 06 Apr 2022 13:30:29 +0200
parents 18d5461bec5d
children
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1 // This is Free Software under GNU Affero General Public License v >= 3.0
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2 // without warranty, see README.md and license for details.
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3 //
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4 // SPDX-License-Identifier: AGPL-3.0-or-later
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5 // License-Filename: LICENSES/AGPL-3.0.txt
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6 //
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7 // Copyright (C) 2019 by via donau
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8 // – Österreichische Wasserstraßen-Gesellschaft mbH
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9 // Software engineering by Intevation GmbH
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10 //
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11 // Author(s):
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12 // * Sascha L. Teichmann <sascha.teichmann@intevation.de>
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13
4558
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14 package common
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15
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16 // Linear constructs a function which maps x1 to y1 and x2 to y2.
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17 // All other values are interpolated linearly.
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18 func Linear(x1, y1, x2, y2 float64) func(float64) float64 {
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19 // f(x1) = y1
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20 // f(x2) = y2
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21 // y1 = x1*a + b <=> b = y1 - x1*a
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22 // y2 = x2*a + b
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23
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24 // y1 - y2 = a*(x1 - x2)
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25 // a = (y1-y2)/(x1 - x2) for x1 != x2
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26
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27 if x1 == x2 {
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28 return func(float64) float64 {
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29 return 0.5 * (y1 + y2)
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30 }
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31 }
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32 a := (y1 - y2) / (x1 - x2)
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33 b := y1 - x1*a
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34 return func(x float64) float64 {
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35 return x*a + b
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36 }
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37 }